Initially, following the Soviet Invasion Timeline, the Soviets sought to work with "responsible" members of the American government to establish a quisling regime. Until the press was under firm control, politicians were not shot or executed. In extreme conditions, they were removed from their seats by a vote of Congress.
A "new, unified" CPUSA (Communist Party, United States of America) was established from among American Communist splinter groups, left-wing groups such as the New Alliance and Socialist Labor Parties, and anyone else willing to participate. It rapidly expanded in size as careerists and liberal opportunists joined to take advantage of the privileges they obtained.
After a year or so of interim government, new elections were held in which Communist Party members were elected by wide margins. No coercion was applied to the voters; however, poll-watchers kept records of how individuals voted, which were the basis for deportations and executions once control was firm. The actual voting was irrelevant, since the data released to the Soviet-controlled press had no basis in fact.
Notorious "right-wingers" in government and some military leaders were tried as war criminals and executed. The Constitution was not materially amended; the Soviet constitution was, if anything, even more liberal in awarding rights to its citizens, and the Soviet government had never found it a noticeable restraint on its actions. Properly interpreted and ignored when necessary, a constitution is nothing more than a piece of paper.
Thus, the last pre-Occupation Senators were not removed from office for at least 6 years after the Occupation began. This did not prevent the Soviets from doing what they wished. The only opposition of any importance will came from the Supreme Court, which was easily replaced. Some justices resigned ("For personal reasons," as the press releases said); others died in mysterious circumstances. Eventually, Congress simply passed a law stripping the Court of its powers to review legislation (which, it must be remembered, is nowhere enshrined in the Constitution).
Once the CPUSA was in firm control of the organs of government, it announced a "reorganization" of American territory "at popular demand." The states were abolished. Alaska was ceded to the Soviet Union. An "independent" Confederate Soviets of America was established, as was a Texas Federated Soviet Republic. The remaining 35 states were organized into the United American Soviets (with several member-republics); sections of the southwest were returned to Soviet Mexico. An "Amerindian Peoples' Autonomous Region" was established, partly as an attempt to enlist support from Native Americans, partly as a convenient dumping ground for Indian groups the new government disposed from areas containing valuable minerals. Puerto Rico became "independent," as did Hawaii.
Eventually, one single world government was established, with each "independent" nation sending representatives to its deliberative body. This world government was called the Union of Soviet Socialist Republics. Its capital was Moscow.
Within three years of occupation, mass deportations and executions began. Small business was nationalized; most distribution businesses and shops were closed down. Unemployment was abolished, through the simple expedient of declaring unemployment to be "hooliganism," and sending hooligans to slave labor camps for "reeducation."
Private education was abolished, and mandatory public education became truly mandatory and public. The quality of education even improved, as children learned that failing to do homework, attend school, and pay attention were followed by real and severe punishment.
Needless to say, all forms of public entertainment (including television, videos, movies, books, magazines, radio, records, games, etc., etcs.) came under stringent censorship. Popular culture (genre fiction, rock, comic books, roleplaying, etc.) was abolished as "decadent" and "bourgeois."
Goods virtually evaporated from the remaining state-run stores. Shopkeepers, bureaucrats who depended on faceless bureaucracies and not customers for their income, now had no incentive to treat customers courteously or to provide them with the goods they desired. Currency became increasingly irrelevant; no quantity of dollars could get you quality goods. Only hard currency (gold) and connections could do that. The new elite - Party members, bureaucrats, collaborators - lived well. Everyone else lived miserably, in crowded quarters, with an inadequate diet and few outlets for recreation.
All education contained a huge dollop of propaganda. Children were encouraged to denounce their parents for "counterrevolutionary activities." The whole of society came to realize that criticizing the new regime in any fashion was terribly dangerous, and all criticism came to a halt. The true state of affairs became a secret from virtually the whole population; most of the country did not know about the gulags, and would not believe it if told. Children, fed Soviet propaganda at school and failing to receive contrary views from frightened parents, came to believe. Three generations from the Occupation, America is a contented and enthusiastic slave to its Soviet masters.