American voters head to the polls on Tuesday in midterm elections that will determine control of Congress and serve as a referendum on President Donald Trump's second term.

All 435 seats in the House of Representatives and 35 of the 100 Senate seats are contested. Democrats are widely favored to retake the House, where they need three seats, but face a greater challenge in the Senate, where they need four. A Reuters/Ipsos poll completed Monday found 46 percent of registered voters would vote for Democrats compared with 38 percent for Republicans. Trump's approval rating stands at 32 percent.

Trump devoted his final major speech before voting day to touting renovations of the Lincoln Memorial Reflecting Pool in Washington. The 80-year-old former real-estate developer spent more than 20 minutes discussing pipes, joints, caulking, granite resurfacing, algae and leaks. He later spoke by telephone on Fox News' "Hannity" show, urging Republicans to "pretend I'm on the ballot." "If our people vote, we win in a landslide," Trump said.

The Supreme Court on Monday rejected the Trump administration's attempt to temporarily block California from counting mail-in ballots from more than 20,000 registered voters whom federal officials alleged were likely non-US citizens. A US judge also ordered the administration to stop demanding that California segregate ballots cast by people on lists of suspected noncitizens. Trump has offered a $1 million reward for evidence of electoral fraud and said he would only accept the result if the elections are "honest."

In Michigan, Democratic candidate Abdul El-Sayed, a physician and former public health official, is attempting to become the first Muslim elected to the Senate. He faces Republican Mike Rogers in a tight race that grew heated when Representative Haley Stevens, who lost the Democratic primary to El-Sayed, switched to backing Rogers. El-Sayed's campaign said it raised $2.4 million on Sunday. In Texas, Democrat James Talarico faces Trump-backed Attorney General Ken Paxton, who warned that "if we lose Texas, we lose America."

If the Senate comes down to a single seat, Alaska could be the tiebreaker, where vote counting may take weeks due to the state's election system. Trump said Monday he is considering "redoing" the Alaska Senate election if Republicans lose, alleging that candidate Mary Peltola participated in a campaign to recruit a third candidate with the same name as her rival.

Early voting has set a record with 57 million votes cast as of Monday afternoon, up from 45 million in all of the 2022 midterms. Election forecaster Nate Silver's model gives Democrats a 95 percent probability of winning the House and 80 percent for the Senate. Prediction market Kalshi puts the probability of Democrats winning both chambers at 73 percent. Trump campaigned in 20 states over the past 32 days. He plans no public appearances on Tuesday, with a private reception scheduled in the White House East Room for election night.