The United States of America (USA), commonly known as the United States (U.S.) or America, is a federal republic composed of 50 states that existed before the Republic of Gilead and the events of the television series/novel. A coup d'état, staged by a radical Christian group called the Sons of Jacob, assassinates the President, all members of Congress, as well as the judges of the Supreme Court with three separate "attacks". The SoJ promptly seized control of the U.S. government, and shortly afterward, suspended the U.S. Constitution and terminated its existence, replacing it with Gilead and its set of draconian religious laws.
The book is very sparing with giving details as to what exactly happened to the American government and the current state of world affairs, probably since the story is told only from the point of view of Offred/June. However, the television series is shown to be more specific as to the background of the novel's universe. Some things revealed include the series seems to take place in the present day or the near future, as flashbacks shows June and Moira using iPhones and the inside of a contemporary looking hospital. In addition, it can be estimated the fall of the United States took place around 3 to 4 years prior to the events of the series. The show divulges that June's husband Luke successfully crossed the border into Canada three years before the story begins, while June and their daughter Hannah were captured trying to flee. It is also revealed that Commander Fred Waterford was an original member of the SoJ and had advance knowledge of the plan to attack and take down the US government (Fred would pass this information on to his wife Serena Joy, who also is shown to be complicit in the creation of Gilead). As a commander, Waterford likely played an active role in the takeover itself. He also mentions at one point a meeting among the group was delayed because of a few members being followed by FBI agents (this can also be seen as evidence that the US Government was well aware of the existence of the Sons of Jacob and their plans for the United States; and the US Government had contingency plans formulated and in place should they fail to stop the Sons of Jacob from carrying out their coup d'état).
Other pieces of information the TV series provides is that the U.S. still exists as a rump state, maintaining control of only the states of Alaska and Hawaii (this is shown by an American flag possessing only two stars), with the capital of the diminished country being the city of Anchorage. There's a possibility the states that make up the western United States (e.g., Texas and California) are still independent of Gilead control, and may have become smaller, independent nation-states. Territories like Guam, Puerto Rico, the U.S. Virgin Islands, and Guantanamo Bay, Cuba are more than likely still on side with the U.S. government-in-exile and haven't been incorporated into the Republic of Gilead.
Before the Sons of Jacob's coup d'état against the United States government, the United States Armed Forces were the official standing military of the United States of America.
The U.S. Armed Forces consisted of the United States Army, the United States Air Force, the United States Navy, the United States Marine Corps, and the United States Coast Guard. At the state-level, each American state had its own National Guard and Air National Guard forces that operated under control of each territory's governor in times of emergency.
After the Sons of Jacob's coup d'état and the establishment of the Republic of Gilead, it appears that the vast majority of the United States Armed Forces (and it's assets) didn't side with the new regime, and instead, maintained their loyalties to the U.S. government-in-exile, and are actively fighting to liberate the United States from Gileadean control (this is possibly due to the US Armed Forces staying loyal to their Oath of Enlistment in which US military personnel swore to "uphold and defend the Constitution of the United States from all enemies, foreign and domestic" as well as the US military being well aware of the Sons of Jacob's planned coup d'état and had contingency plans in place like the rest of the United States Government in case the SoJ succeed in their coup and the US Government was overthrown).
One piece of strong evidence to back up this theory can be seen in the 2017 TV series, with the total absence of uniformed military officers among the ranks of the Republic of Gilead's leadership. Another piece of evidence that further solidifies the U.S. Armed Forces opposition to the Republic of Gilead is of reports of the U.S. Army and the Illinois National Guard fighting the Republic of Gilead's Angel and Guardian forces in the city of Chicago, Illinois and, possibly; in the state of Florida with the US military, the Florida National Guard, and local rebel and militia units fighting Gilead's forces for control of the state. In Episode 7 of The Handmaid's Tale, there's strong evidence the U.S. military was active in fighting against the Sons of Jacob/Republic of Gilead's forces in the immediate period of time after the Sons of Jacob's coup against the American government. One example is Zoe's backstory of being with the US Army in South Carolina in the immediate time period after the Sons of Jacob's coup and the establishment of the Republic of Gilead. During this period of time, Zoe and a unit of U.S. Army soldiers she was stationed with in South Carolina discovered an early Handmaid training-center (in the form of a high school gym) under Guardian control.
In regards to the U.S. Armed Forces fighting the Republic of Gilead, a strong possibility exists that America's allies (e.g., Canada and the member-states of NATO) are providing arms and supplies to exiled American forces in their fight to liberate the country from Gileadean control. There is also a strong possibility the U.S. Armed Forces still have the large bulk of its military assets, personnel, and America's nuclear arsenal under its direct control, since the U.S. Armed Forces didn't side with the Republic of Gilead, and still remained loyal to the U.S. government-in-exile in Anchorage, Alaska.
A strong possibility also exists that the U.S. Armed Forces (and a good portion of its nuclear arsenal) is based in Canada after the rise of Gilead, and are acting in both a defensive role (in assisting the Canadian Armed Forces in protecting Canada from the Republic of Gilead) and in an offensive role (in providing military forces and supplies to other U.S. military units across the border in their war against the Republic of Gilead).
Anti-Gilead rebels and militiasEdit
Besides the U.S. Armed Forces, the citizens of the United States of America have also taken up arms against the tyrannical Republic of Gilead (the United States has one of the highest levels of civilian firearm-ownership rates in the world, and the Second Amendment to the United States Constitution recognizes that, "[the] right of the people to keep and bear arms shall not be infringed").
Multiple rebel groups and pro-U.S./anti-Gilead militias are still fighting Gilead's forces across the former continental United States (and within the territories currently held or controlled by the Republic of Gilead), with these resistance fighters (and regular U.S. military forces) fighting Gilead's forces in the Blue Hills of Massachusetts, in the Southern states (with reports of resistance fighters from the Baptist Church forming militia-units to fight against Gilead's forces) and in the state of Florida. Although, it is not revealed if these rebel and militia organizations are directly affiliated with the American government, there's a possibility the rebel and militia-units are working, corresponding, and co-ordinating their efforts with the U.S. military in their war against the Republic of Gilead.
Among the multiple rebel and militia units fighting the Republic of Gilead is the Mayday movement.
American refugee communities in CanadaEdit
In the 2017 TV series, Luke is shown to travel to a section of Toronto, Ontario, Canada called "Little America," where a community of American refugees and government officials representing the U.S. government-in-exile in Canada are located. The interior of the U.S. consulate which Luke visits is overflowing with photos of missing persons.