The Secret Sentry (5 page)

But the Chinese were not bluffing. On October 1, South Korean troops crossed the 38th parallel and marched into North Korea.
The next day, the Chinese Communist Party’s Politburo decided to intervene militarily in the Korean War, with Mao Tse-tung
ordering 260,000 Chinese troops to begin crossing the Yalu River on October 15.
²³

The Chinese leadership in Beijing made one last final effort to head off war with the U.S. Shortly after midnight on the morning
of October 3, 1950, Chou En-lai called in Ambassador Panikkar and told him that if U.S. troops crossed the 38th parallel,
China would send its forces across the Yalu River to defend North Korea. On the same day, the Dutch chargé d’affaires in Beijing
cabled his foreign ministry in the Hague quoting Chou En-lai to the effect that China would fight if U.N. forces crossed the
38th parallel.
²⁴
But Washington refused to pay heed to these warnings, which were dismissed in their entirety as being nothing more than a
bluff. On October 5, the first American combat troops were ordered to cross the 38th parallel and advance on the North Korean
capital of Pyongyang. By this singular act, General MacArthur committed U.S. and U.N. forces to a course of action that was
to have dire consequences for everyone involved.
²⁵

On the morning of October 15, Mao sent a cable to his military commander in Manchuria, General Peng Dehuai, ordering him to
send the first Chinese army units across the Yalu River into North Korea. On the night of October 15–16, the 372nd Regiment
of the Chinese 42nd Army secretly crossed the Yalu. The die had been cast. China had entered the Korean War.
²⁶

Declassified documents confirm that AFSA failed to detect the movement of the more than three hundred thousand Chinese soldiers
into Korea, largely because the Chinese forces operated in complete radio silence.
²⁷
But SIGINT did pick up a number of changes in Soviet, Chinese, and North Korean military activities indicating that something
significant was happening across the border in Manchuria. On October 20, the CIA sent President Truman a Top Secret Codeword
memo (which the CIA has steadfastly refused to fully declassify) revealing that SIGINT and other intelligence sources indicated
that the Chinese intended to intervene militarily in the Korean War to protect their interests in the Suiho hydroelectric
complex in North Korea. According to the report, SIGINT “noted the presence of an unusually large number of fighter aircraft
in Manchuria.”
²⁸
The next day, October 21, AFSA reported that intercepts of Chinese radio traffic showed that during the first three weeks
of October, three Chinese armies had been deployed to positions along the Yalu River. Also on October 21, AFSA reported that
during the previous week, twenty troop trains carry ing Chinese combat troops had been sent from Shanghai to Manchuria and
more were on their way.
²⁹

Sadly, all of this intelligence data was again ignored or discounted because it ran contrary to the prevailing wisdom of the
U.S. intelligence community. For example, the October 18, 1950, edition of the CIA’s
Review of the World Situation
stated, “Unless the USSR is ready to precipitate global war, or unless for some reason that Peiping leaders do not think that
war with the U.S. would result from open intervention in Korea, the odds are that Communist China, like the USSR, will not
openly intervene in North Korea.”
³⁰
In Tokyo, MacArthur chose to ignore the SIGINT. One of MacArthur’s senior intelligence officers, Lieutenant Colonel Morton
Rubin, remembered personally briefing the general and his intelligence chief, General Charles Willoughby, on the Chinese troop
movements appearing in SIGINT, but the intelligence reports apparently did not convince either man that the Chinese threat
was real. Lieutenant General Matthew Ridgway, who later was to replace MacArthur as commander of U.S. forces in the Far East,
recalled that “the great fault over there was poor evaluation of the intelligence that was obtained. They knew the facts,
but they were poorly evaluated. I don’t know just why that was. It was probably in good part because of MacArthur’s personality.
If he did not want to believe something, he wouldn’t.”
³¹

The result was that when the Chinese launched their first offensive in Korea, it achieved complete surprise. Striking without
warning, between October 25 and November 2, 1950, three PLA armies decimated the entire South Korean 2nd Corps and a regiment
of the U.S. 1st Cavalry Division near the North Korean town of Unsan. The Chinese troops then quietly withdrew back into the
hills to prepare for the next phase of their offensive.
³²

After the Unsan fiasco, the entire U.S. intelligence community went into a state of denial, refusing to accept the fact that
the Chinese military was in Korea. In Washington, the CIA’s intelligence analysts concluded, “There has been no definitive
evidence of Soviet or Chinese intervention in Korea.” On October 30, the CIA’s
Daily Summary
opined that “the presence of Chinese Communist units in Korea has not been confirmed. CIA continues to believe that direct
Chinese Communist intervention in Korea is unlikely at this time.” In Korea, the Eighth Army reported that despite the fact
they held seven Chinese POWs, they were “not inclined to accept reports of substantial Chinese participation in North Korean
fighting.”
³³

What is curious is that all the assessments coming out of the intelligence staffs in Washington and Tokyo were directly contradicted
by what the chatty Chinese POWs captured at Unsan were telling their interrogators, which was that whole Chinese combat divisions
were then operating inside Korea.
³⁴
When CIA officers in Korea had the temerity to cable Washington with the results of the interrogations of the Chinese prisoners,
Willoughby barred CIA personnel from further access to the POW cages, telling the Eighth Army’s intelligence chief to “Keep
him [the CIA station chief in Korea] clear of inter rogation.” It was the prototypical case of shooting the messenger.
³⁵

In the weeks that followed, an increased volume of disquieting intelligence came out of AFSA indicating that the Chinese military
was preparing to attack. In early November, AFSA reported that the Chinese had just moved three more armies by rail to Manchuria,
and that the security forces guarding Beijing had just been placed on a state of alert.
³⁶
On November 24, the CIA issued a report based on COMINT, which revealed that an additional one hundred thousand Chinese troops
had just arrived in Manchuria and that the Chinese were shipping thirty thousand maps of North Korea to its forces in Manchuria.
³⁷
AFSA also produced intelligence indicating that MacArthur was looking for a fight with the Chinese. On November 11, Army
chief of staff J. Lawton Collins sent a Top Secret Codeword “Eyes Only” message to MacArthur containing the text of a decrypted
message from the Brazilian ambassador in Tokyo, Gastão P. Do Rio Branco, to his home office in Rio de Janeiro. According to
the decrypt: “Speaking with . . . frankness, he [MacArthur] told the President that it would be better to face a war now than
two or three years hence, for he was certain that there was not the least possibility of an understanding with the men in
the Kremlin, as the experience of the last five years has proved. He felt, therefore, that in order to attain peace it is
necessary to destroy the focus of international bolshevism in Moscow.”
³⁸

The general got his wish. At 8:00 p.m. on the night of November 25, 1950, the Chinese army struck once again, this time with
even greater force, decimating the combined U.S. and South Korean forces stretched out along the Yalu River, sending the allied
forces reeling backward in retreat. The final word appropriately goes to MacArthur, who sent a panicky Top Secret cable to
Washington on November 28 including the now-famous line: “We face an entirely new war.”
³⁹

World War III Cometh

On the night of November 30, General Walker’s Eighth U.S. Army broke contact with the Chinese People’s Liberation Army (PLA)
forces along the Yalu River and began a two-week-long, 120-mile retreat south to the Imjin River, north of Seoul. During this
critically important two-week period, there was no contact whatsoever between the Eighth Army and the pursuing Chinese forces,
which resulted in the entire U.S. intelligence community being left almost completely in the dark concerning the PLA forces.

Declassified documents show that during the Eighth Army’s hasty retreat southward, SIGINT was not able to provide much in
the way of substantive intelligence information about the strength, locations, or movements of the three hundred thousand
Chinese troops following them. Apart from exploiting intercepted low-level railroad traffic, AFSA had devoted virtually no
resources to monitoring Chinese military communications prior to the Chinese intervention in Korea. Even if the U.S. military
SIGINT units in the Far East were intercepting Chinese radio traffic, they didn’t have any Chinese linguists who could translate
the intercepts. The result was that as of mid-December 1950, senior U.S. military commanders found themselves in the embarrassing
position of having to admit that information from all sources was “vague and indefinite on the exact disposition of CCF [Chinese
Communist Forces] in Korea.”
⁴⁰

On December 23, Lieutenant General Walker was killed in a jeep accident. He was replaced by Lieutenant General Matthew Ridgway,
one of the U.S. Army’s best field commanders, who flew in from Washington on December 26 and discovered that the intelligence
situation map at his Eighth Army headquarters in Seoul showed only “a large red goose egg” north of his front lines, indicating
an estimated 174,000 PLA troops—which was all that army intelligence then knew about the estimated strength and position of
the Chinese forces. While American units had obtained some intelligence from two captured Chinese soldiers, everything else
that Eighth Army G-2 believed to be true about Chinese PLA troop dispositions was pure speculation.
⁴¹

But while AFSA was producing no intelligence about the Chinese forces, it continued to generate vast amounts of data about
the North Korean military forces because of its continued ability to read all major North Korean ciphers. According to a declassified
NSA history, as of December 1950 AFSA was solving and translating 90 percent of the encrypted North Korean messages it was
intercepting.
⁴²
For example, SIGINT derived from these communications was instrumental in allowing the U.S. Navy to successfully evacuate
by December 24 the entire U.S. Tenth Corps plus tens of thousands of refugees from the North Korean port of Hungnam. SIGINT
also confirmed that the Chinese and North Koreans did not intend to disrupt the evacuation by air attack.
⁴³

The Chinese January 1951 Offensive in Korea

On New Year’s Eve, December 31, 1950, seven Chinese armies launched a major offensive across the 38th parallel, which shattered
the Eighth U.S. Army’s defensive positions along the Imjin River. Seoul fell for a second time on January 4, 1951, the last
U.S. forces having fled the city the night before.
⁴⁴

As American forces struggled to keep a foothold in Korea, there was little SIGINT to offer by way of intercepts of Chinese
military radio transmissions because of a lack of Chinese linguists, and also because almost all available radio intercept
resources were focused on the more productive North Korean military target. As a result, the SIGINT organizations were producing
virtually nothing in the way of usable tactical intelligence on the Chinese military at a time when U.S. field commanders
in Korea were desperate for
any
tidbit of information.
⁴⁵

Despite these inherent weaknesses, SIGINT performed brilliantly during the month of January, helping Lieutenant General Ridgway’s
Eighth Army decimate the newly rebuilt North Korean Second and Fifth Corps as they strove to break through the American–South
Korean defensive lines in the Korean central highlands. When the South Korean Second Corps collapsed, it was SIGINT that revealed
the North Korean attack plans, with a decrypted January 2 message from the North Korean general staff in Pyongyang ordering
the commander of the North Korean Fifth Corps to push through the breach and “pursue the enemy, not giving them time to rest.”
⁴⁶
By January 15, Eighth Army G-2 was convinced from an accumulation of information derived from SIGINT that the Chinese and
North Koreans were readying themselves for yet another major offensive. But SIGINT revealed that the enemy forces had taken
murderously heavy losses in the fighting up to that point, and that certain key units were barely combat ready. Another critically
important piece of intelligence provided by SIGINT was a January 23 decrypted message revealing that the entire Chinese Ninth
Army Group was reforming near the North Korean port of Wonsan and would “take a rest until the end of February.” Ridgway now
knew that three Chinese armies would not be taking part in the upcoming Chinese–North Korean offensive.
⁴⁷

Acting on this intelligence, on January 24, Ridgway launched a counterattack called Operation Thunderbolt, which by January
31 had forced the Chinese forces back toward Seoul. By the end of January, SIGINT revealed that the Chinese and North Korean
forces were exhausted, short of ammunition and supplies, and decimated by battlefield casualties and infectious diseases.
⁴⁸

The Ides of March: The Russians Are Here!

In late March 1951, an event took place that literally overnight changed the way the entire U.S. intelligence community thought
about the war in Korea. According to declassified documents, on March 30 the U.S. Air Force radio intercept unit in Japan,
the 1st Radio Squadron, Mobile, commanded by Major Lowell Jameson, “made one of the most important contributions to Air Force
Intelligence in its history.” Intercepts of MiG radio traffic confirmed the long-held suspicion that the Russians were controlling
the air defense of North Korea and Manchuria, not the Chinese or the North Koreans.
⁴⁹
As a former air force Russian linguist stationed in the Far East recalled, “we were actually monitoring the Soviet Air Force
fighting the American Air Force and we were listening to the Soviet pilots being directed by Soviet ground control people
to fight the Americans. We were fighting our own little war with the Soviets.”
⁵⁰