The film is unrelated to the 1985 Chuck Norris film of the same name, although bearing some slight similarities.
In a New York City bar, the brooding, mysterious forecaster Mr. Ohman (Dan O'Herlihy) is sitting and drinking from a very large brandy glass. He gets into discussions with a cross-section of affluent Americans at the bar, including local television newscaster Vince Potter (Gerald Mohr), beautiful young New York society woman Carla Sanford (Peggie Castle), a California industrialist, a rancher from Arizona, and a Congressman. International news is bad, but these Americans do not want to hear it. While they all dislike Communism and appreciate the material wealth they enjoy, they also want lower taxes and don't see the need for industrial support of government. As he swishes the brandy around his snifter, Ohman tells the others that many Americans want safety and security, but do not want to make any sacrifices for it.
Suddenly the news becomes worse. "The Enemy" is staging air attacks over Seal Point, Alaska and then Nome. Paratroops have landed on Alaskan airfields. Soon the enemy's plan of attack becomes clear: civilian airfields are captured as staging areas while military airfields are A-bombed. The United States fights back and attacks the enemy's homeland with Convair B-36 missions, but the enemy steadily moves into Washington and Oregon. Shipyards in Puget Sound are A-bombed with large casualties.
Meanwhile, the Americans at the bar scramble to return to their lives to do what they can against the enemy, now that it is too late. Potter and Sanford fall for each other ("War or no war, people have to eat and drink ... and make love!"). He continues to broadcast, while she volunteers to help run a blood drive. The industrialist and the rancher both return home to find themselves on the front lines: the former caught in the battle for San Francisco, the latter in the destruction of Boulder Dam by a nuclear missile. The President of the United States makes ineffectual broadcasts with inflated claims of counter-attacks to rally the morale of the people. The enemy continues to advance with stealth attacks by troops dressed in American uniforms, including a paratrooper attack on the Capitol that kills the Congressman. New York is A-bombed, and Potter is soon killed during a broadcast. Sanford, confronted by an "enemy" soldier, jumps from a balcony.
Suddenly, the image of her falling body appears in Ohman's brandy snifter. All five suddenly find themselves back in the bar, having just emerged from a hypnotic state Ohman had induced. After reassuring themselves that the recent events (including their deaths) haven't happened, they hurry off to take measures to boost military preparedness. Potter and Sanford "resume" their romance.
It was the second film from American Pictures Corporation, who had just made their first film, Captive Women. The company consisted of Albert Zugsmith, Peter Miller, Aubrey Wisberg and Jack Pollexfen with Joseph Justman as producer. They planned to make six films a year for five years out of a fund of $3.5 million. Robert Smith wrote the script. The film had the co operation of the US Civil Defence.
Harold Daniels was to direct but he was instead assigned to American Pictures Corporation's, Port Sinister. He was replaced by Alfred E. Green. Ron Randell was meant to appear in the cast but had to pull out. William Schallert replaced Clete Roberts. Gerald Mohr replaced Michael O'Shea. Filming started 26 March 1952.
"The Enemy" is never named but is clearly meant to be taken as the Communist Soviet Union, given their approach through Alaska, pseudo-Slavic accents, "People's Army" proclamations, and use of Soviet military aircraft (Yakovlev Yak-17s and Mikoyan-Gurevich MiG-15s and Tupolev Tu-4 bombers, a clone of the American Boeing B-29 Superfortress). Principal photography began in early April 1952 at Motion Picture Center Studios.
Much of the film's running time is taken up with inconsistent and inappropriate combat stock footage. This is relatively aseptic, and sometimes unintentionally humorous: American Fairchild C-82 Packet transports drop "enemy" paratroopers on Washington, D.C. (However these troops are disguised as an American Airborne unit so the aircraft may be part of the act.) Some of the individual encounters between the enemy and Americans are typical of Red Scare material of the time.
On a philosophical level, Invasion, U.S.A. is also often viewed as humorously (and unintentionally) ironic, as the lesson it communicates encourages citizens to subordinate their individual needs and desires to that of the state in order to combat Communism.
Phyllis Coates and Noel Neill, two future Lois Lane actresses, and William Schallert, a B-movie stalwart, all have small parts in the film.
In a contemporary review of Invasion, U.S.A. in Variety stated: "This production imaginatively poses the situation of a foreign power invading the US with atom bombs. Startling aspects of the screenplay [from a story by Robert Smith and Franz Spencer] are further parlayed through effective use of war footage secured from the various armed services and the Atomic Energy Commission."
The film was commercially successful, bringing in net profits of almost a million dollars by one account and grossing $1,200,000 in the United States by another. It was re-released in 1956. Invasion, U.S.A. was subsequently shown on television in the late 1960s, but then was not widely viewed for a long time. In 1994, it was spoofed as Episode 602 on the movie-mocking television show Mystery Science Theater 3000.
In 1998, Invasion, U.S.A. was released on VHS, then on DVD in 2002. A special edition in 2009 featured two original Civil Defense Department audio recordings on the alternate DVD audio track: The Complacent Americans and If the Bomb Falls: A Recorded Guide to Survival; the 1956 re-issue theatrical trailer; and interviews with stars, Dan O'Herlihy, William Schallert and Noel Neill. The original and controversial "Red Scare" short Red Nightmare, narrated by Jack Webb, was also included in the bonus features.