How the US Midterms Work, and Why They Matter for Trump's Second Term

On November 3, American voters will go to the polls in an election that will not put anyone in the White House but will shape what the man already there can do. These are the midterms, held every four years at the halfway point between presidential contests, and this year they double as a verdict on Donald Trump's second term. His approval ratings are currently at a record low.

The ballot is large. All 435 seats in the House of Representatives are up, each member representing one district, with districts apportioned by population. That is why Wyoming, large in area but thinly settled, has a single House seat, while much smaller New Jersey has 12. House terms last two years. In the Senate, which has 100 seats, two for each state regardless of size, members serve six-year terms and roughly a third of seats come up every two years. This time 35 are being contested, so not every state will choose a senator. Voters in 36 states will also elect governors, who serve four-year terms in most states. Those offices matter because so much is decided at state level, from abortion law to education to how elections are run.

The starting position is tight. Republicans control both chambers, but narrowly. The House currently has 218 Republicans, 214 Democrats and one independent who usually votes with the Republicans, with two seats vacant. In the Senate there are 53 Republicans, 45 Democrats and two independents who usually vote with the Democrats. If the Senate splits 50:50, the vice president breaks the tie, which today means JD Vance.

J. Miles Coleman, an election analyst at the University of Virginia's Center for Politics, has described midterms as often a referendum on the president and the party in power. When voters are content, that party tends to do better; when they are mostly dissatisfied, it does worse. Speaking to CBS at the end of October, Coleman said it would be a surprise if Democrats did not at least take the House.

The arithmetic supports him. Democrats need a net gain of four House seats to reach 218 and a majority. Of the 435 races, only a few are still seen as toss-ups, among them districts in Iowa, Virginia and Montana. Turnout is usually lower in midterms than in presidential years, but the stakes are real: although the presidency holds substantial executive power, most federal decisions need Congress's approval. A Republican majority in both chambers makes it considerably easier for Trump to govern as he wishes. If Democrats win one or both chambers, changes to domestic or foreign policy become harder.

The Senate offers the most surprising contest. Democrats need four more seats there, and one possible pickup is Texas, where polls put Democrat James Talarico level with Republican Ken Paxton. That alone is notable: no Democrat has won statewide in Texas since 1994. Talarico has even drawn support from some members of the Bush family, the Republican dynasty of former presidents George H.W. Bush and George W. Bush.

The governors' races carry their own possible milestone. A Black woman could become a state governor for the first time in US history. In Minnesota, Democrat Amy Klobuchar faces Black Republican Lisa DeMuth, but DeMuth is unlikely to win in a state that generally votes Democratic, where Klobuchar, a senator there for almost two decades, is far better known. Georgia is different: Black Democrat Keisha Lance Bottoms is running against Republican Rick Jackson, the latest polls suggest a neck-and-neck race, and Bottoms has a realistic chance.

Watch the four-seat House gap, the Texas Senate race and Georgia's governorship on November 3. Together they will show how much room Trump has left to govern.