10 January
Soviet intelligence defector Walter Krivitsky has the first of several debriefings at the Department of State.

26 June
President Roosevelt secretly gives the Federal Bureau of Investigation (FBI), the Military Intelligence Division (MID), and the Office of Naval Intelligence (ONI) exclusive responsibility for counterespionage.

23 August
Germany and USSR sign Non-Aggression Pact.

1 September
World War II begins as Germany invades Poland.



21 May
President Roosevelt authorizes the FBI to conduct warrantless electronic surveillance of persons suspected of subversion or espionage; surveillance was to be limited insofar as possible to aliens.

5 June
FBI-MID-ONI "Delimitation Agreement" further specifies the division of labor in domestic intelligence work.

28 June
The Alien Registration Act (the "Smith Act") criminalizes conspiracy to overthrow the government, requires resident aliens to register, report annually, and provide notice of address changes.

20 August
KGB agent Ramon Mercader assassinates Leon Trotsky in Mexico.



10 February
Walter Krivitsky found dead of a gunshot wound in a Washington hotel; the police rule his death a suicide.

5 May
Federal agents arrest Amtorg employee and KGB New York rezident Gaik Ovakimian for violating the Foreign Agents Registration Act.

22 June
Germany invades Russia.

29 June
FBI arrests 29 German military intelligence agents, crippling Germany's clandestine operations in the United States.

23 July
US Government allows Ovakimian to leave the country.

25 September
London KGB rezident Anatoli Gorski informs Moscow that his agent reports London has decided to build an atomic bomb.

7 December
Japanese aircraft attack Pearl Harbor; America enters the war.

25 December
Senior KGB officer Vassili M. Zarubin arrives in San Francisco on his way to succeed Ovakimian as New York rezident.



20 March
MID's Special Branch begins producing daily "Magic Summaries" analyzing foreign diplomatic messages for the White House and senior military commanders.

13 June
The Office of the Coordinator of Information becomes the Office of Strategic Services (OSS), subordinate to the Joint Chiefs of Staff.

30 June
Interagency agreement divides signals intelligence duties: Navy assigned to handle naval codebreaking; the US Army's Signals Intelligence Service to handle diplomatic and military traffic; and the FBI works clandestine radio communications.

8 July
President Roosevelt bars all agencies except the FBI and the armed services from code-breaking activities. The services interpret this directive as authorization to deny signals intelligence to OSS.



1 February
US Army's renamed Signal Security Agency (SSA) formally begins work on Russian diplomatic traffic.

10 April
KGB New York rezident Vassili M. Zarubin meets CPUSA official Steve Nelson in Oakland and discusses espionage.

15 May
Communist International (Comintern) resolves to disband.

7 August
FBI receives an anonymous Russian letter naming Soviet intelligence officers in North America.

31 October
San Francisco KGB residency acknowledges the receipt of a new codebook.



1 May
The KGB, apparently on short notice, changes the indicator system for its cables, leaving the one-time pad page numbers en clair.

SSA's Cecil Phillips discovers the new KGB indicator, which is then used to detect "key" duplicated in Trade messages.

OSS purchases Soviet code and cipher material from Finnish sources; the Roosevelt administration orders the material returned to the Soviet Embassy in Washington.

15 December
The War Department transfers operational control of SSA from the Signal Corps to MID.



12 April
President Roosevelt dies; Harry Truman sworn in as his successor.

27 April
A US Army Target Intelligence Committee (TICOM) team finds Russian code and cipher material in a German Foreign Office cryptanalytic center in a castle in Saxony-Anhalt.

8 May
Germany surrenders.

10 May
FBI conducts a lengthy debriefing of former Soviet agent Whittaker Chambers.

Earl Browder ousted as leader of the Communist Political Association, which reclaims its old name, the Communist Party of the United States (CPUSA).

16 July
The Manhattan Project detonates the world's first nuclear explosion, Trinity, in New Mexico; Soviet agents had warned Moscow in advance.

14 August
Japan capitulates.

5 September
Soviet GRU code clerk Lt. Igor Gouzenko defects in Ottawa.

6 September
The War Department authorizes merger of SSA with selected Signal Corps units to form the Army Security Agency (ASA), under MID.

12 September
US-UK signals intelligence Continuation Agreement extends wartime cooperation in this field.

20 September
President Truman dissolves OSS.

7 November
Elizabeth Bentley interviewed at length for the first time by FBI agents about her work for the KGB.



22 January
Truman creates the Central Intelligence Group and the position of Director of Central Intelligence (DCI).

13 June
The State-Army-Navy Communications Intelligence Board adds the FBI and renames itself the United States Communications Intelligence Board (USCIB).

8 July
National Intelligence Authority Directive 5 secretly directs the DCI to conduct, as "services of common concern," all foreign intelligence and counterespionage.

10 July
CIG joins the new USCIB and gains access to signals intelligence.

15 July
A Canadian Royal commission releases its report on the Gouzenko affair to the public.

17 July
Attorney General Tom Clark urges Truman to renew and broaden Roosevelt's 1940 authorization to conduct electronic surveillance on "persons suspected of subversive activities"; the President soon approves.

20 December
ASA's Meredith Gardner translates part of a KGB message containing a list of atomic scientists.



22 March
Executive Order 9835 tightens protections against subversive infiltration of the US Government, defining disloyalty as membership on a list of subversive organizations maintained by the Attorney General.

26 July
President Truman signs the National Security Act of 1947, creating the National Security Council (NSC) and transforming CIG into the Central Intelligence Agency (CIA).

Around 1 September
Col. Carter Clarke briefs the FBI's liaison officer on the break into Soviet diplomatic traffic.

12 December
NSCID-5 reiterates but qualifies DCI's counterespionage authority to avoid precluding certain "agreed" FBI and military counterintelligence activities.



1 July
NSCID-9 puts USCIB under the NSC and increases civilian control of signals intelligence.

20 July
General Secretary Eugene Dennis and 11 other CPUSA leaders arrested and indicted under the Smith Act of conspiring to advocate violent overthrow of the US Government.

31 July
Elizabeth Bentley testifies before the House Committee on Un-American Activities (HCUA), publicly accusing Harry Dexter White and Lauchlin Currie of being Soviet agents.

3 August
Whittaker Chambers names Alger Hiss and Harry Dexter White as Communists in testimony before the HCUA.

19 October
Meredith Gardner and Robert Lamphere meet at Arlington Hall and formally inaugurate full-time FBI-ASA liaison on the Soviet messages.

17 November
Chambers produces the "Pumpkin Papers" to substantiate his new charge that Hiss and White spied for Moscow during the 1930s.

16 December
A federal grand jury indicts Alger Hiss for perjury.

FBI identifies covername SIMA as Justice Department analyst Judith Coplon.



4 March
FBI arrests Coplon and Soviet UN employee Valentin A. Gubitchev in New York.

23 March
Truman approves NSC 17/4, which reconstitutes the secret Interdepartmental Intelligence Conference to coordinate jurisdiction of FBI and military counterintelligence.

20 May
Defense Secretary Louis Johnson directs a quasi-merger of service signals intelligence in a new Armed Forces Security Agency (AFSA), subordinate to the JCS.

23 September
Truman announces that the Soviets have exploded an atomic bomb.

1 October
The People's Republic of China is proclaimed in Beijing.



21 January
Alger Hiss is convicted of perjury.

24 January
Klaus Fuchs confesses to espionage.

9 February
Senator Joseph R. McCarthy, in a speech in Wheeling, West Virginia, brandishes a list of Communists allegedly working in the State Department.

22 May
FBI arrests Harry Gold for espionage.

25 June
North Korean troops invade South Korea.

17 July
FBI arrests Julius Rosenberg.

24 August
AFSA assigns Soviet intercept material a restricted codeword ("Bride") and special handling procedures.

23 September
Congress passes the Internal Security Act (the "McCarran Act"), which it would soon pass again over President Truman's veto. The Act requires Communist-linked organizations to register and allows emergency detention of potentially dangerous persons.



25 May
British Foreign Office officials Donald Maclean and Guy Burgess flee Great Britain to defect to the Soviet Union.

CPUSA announces that the Party will operate as a "cadre organization," with many of its leaders underground.



AFSA detects duplicate key pages in GRU messages.

4 November
Truman creates the National Security Agency (NSA) to supersede AFSA and further centralize control of signals intelligence under the Secretary of Defense and a reconstituted USCIB.



NSA places the "POBJEDA" codebook--recovered in Germany in April 1945--against KGB messages from 1941 through 1943. More than half of the burned codebook proves useable.

5 March
Stalin dies.

6 April
KGB defector Alexander Orlov's story appears in Life magazine; finally alerting the FBI to his residence in the United States.

19 June
Julius and Ethel Rosenberg executed after President Eisenhower again denies executive clemency.

27 July
Armistice signed in Korea.

6 November
Attorney General Herbert Brownell sparks controversy by claiming in a Chicago speech that former President Truman had appointed Harry Dexter White to head the International Monetary Fund despite FBI warnings that White was a Soviet agent.



20 December
CIA's Directorate of Plans creates the Counterintelligence Staff, with James J. Angleton as its chief.



8 March
NSC approves the FBI's proposed "Cointelpro" operation against the CPUSA.

4 June
The Department of State releases Soviet General Secretary Khrushchev's secret speech to the Twentieth Party Congress, in which Khrushchev denounced Stalin's crimes.

Soviet troops suppress a popular uprising in Hungary.



25 January
FBI arrests Jack and Myra Soble for espionage on the basis of evidence provided by double agent Boris Morros.

4 May
KGB officer Reino Hayhanen, en route from the United States, defects at the US Embassy in Paris.

17 June
Supreme Court in Yates v. US rules the government had enforced the Smith Act too broadly by targeting protected speech instead of actual action to overthrow the political system; this ruling makes the Act almost useless for prosecuting Communists.

21 June
Federal authorities detain Hayhanen's superior, KGB illegal Col. Rudolf Abel, in New York.

15 November
Abel is sentenced to 30 years and conveyed to prison.


Historical Document
Posted: Mar 19, 2007 11:31 AM
Last Updated: Jul 07, 2008 02:23 PM