Voters head to the polls Tuesday to decide control of Congress in a midterm election that could have major implications for the remainder of President Donald Trump's term in office.

Republicans are defending House and Senate majorities amid the public's frustration over high consumer prices, an enduring war with Iran, the perception of corruption in the government and an immigration crackdown that has swept up American citizens and people in the country legally.

Democrats are hoping to capitalize on Trump's persistently low approval ratings and are widely projected to take back the U.S. House, potentially making House Minority Leader Hakeem Jeffries, D-N.Y., the first Black speaker of the House in U.S. history.

The Senate outlook is hazier, but Democrats have surged late, making races competitive in states that until recently seemed out of reach.

The results of Tuesday's election could shift power in Washington and have a profound effect on Trump's final two years in the White House. Here's what to 1) Will Republican gerrymanders hold?

At Trump's urging, several Republican-led state legislatures began the uncommon process of mid-decade redistricting in 2025, and over the course of 2025 and 2026, redrew their congressional districts to make formerly Democratic districts more winnable.

Democrats responded, setting off a redistricting arms race that — along with the April Supreme Court decision that weakened a key section of the Voting Rights Act, endangering majority-Black districts in the South — gave Republicans an edge on paper heading into the midterms.

But victory in those redrawn districts is far from certain, and, in states including Texas and Florida, many of those seats are up for grabs.

In those two states alone, Republicans redrew nine seats to make them more heavily Republican. But according to the Cook Political Report with Amy Walter, Republicans are favored to win in just three of those.

"The Republican dummy-manders in places like Texas and Florida are falling apart," Jeffries told CNN on Oct. 26. "There's no circumstance where Republicans are gaining five seats in Texas. And no circumstance where they're netting four seats in Florida." The strategy, particularly in Texas, relied in part on Latino and Hispanic voters, who shifted to the right in 2024 but have more recently shown signs of cooling on the GOP, at least in this election.

An Oct. 16 Pew Research Center survey found that 51% of registered Hispanic voters preferred Democratic candidates in 2026, compared with 24% who said they preferred Republicans.

2) States previously thought out of reach now in play Democrats weren't expected to compete in states including Kansas, Mississippi and South Carolina, but Trump backlash has put their Senate races in play.

Sen. Roger Marshall, R-Kansas, is in a fight to keep his seat against Democratic nominee Adam Hamilton in a race the Cook Report shifted to a "toss up" on Oct. 6. Kansas hasn't elected a Democratic U.S. senator since 1932. In ruby red Mississippi, Sen. Cindy Hyde-Smith is still expected to win.

But Democratic challenger Scott Colom has made it a competitive race. The Cook Report shifted the race from "solid R" to "likely R" on Oct. 20. "Every radical policy backed by Adam Hamilton and Scott Colom that excites the DSA's base — from socialist tax hikes to transgender surgeries on children — is a nonstarter in red states like Kansas and Mississippi, where commonsense voters continue to outnumber Democrats," National Republican Senatorial Committee press secretary Bernadette Breslin said in a statement, referring to the Democratic Socialists of America.

In South Carolina, GOP Sen. Darline Graham, who was appointed to finish her brother Sen. Lindsey Graham's term after he died in July, is in a closer-than-expected race against Democrat Annie Andrews. The Cook Report also downgraded that race for Republicans, moving it on Oct. 20 from "likely R" to "lean R." At the same time, Democrats are contending with potential underperformance in states where they've historically done well, including Minnesota and New Hampshire. Losses there could offset gains elsewhere.

Rep. Chris Pappas has only a modest lead in polling for New Hampshire Senate against John E. Sununu, whose brother and father were both governors of the state. In Minnesota, Peggy Flanagan, the state's lieutenant governor and Democratic Senate candidate, is in a tight race against Republican Michele Tafoya, a former sports broadcaster.

The Cook Report rates both the New Hampshire and Minnesota races as "lean D." 3) Democrats eye Texas A statewide win for Democrats in Texas could be a huge morale boost for the party, which fell just short of a Senate seat in 2018 in a state that hasn't been competitive recently.

State Rep. James Talarico got an enticing matchup with a vulnerable candidate when Trump threw his support behind embattled Attorney General Ken Paxton over Sen. John Cornyn in the GOP primary. Polling averages have shown Talarico with a slim lead.

The race will also be key to control of the Senate. Democrats need to flip four Republican seats, while holding all the seats currently in their control to win a majority. Picking up a Texas Senate seat for the first time since the 1980s would help.

But Paxton, who has been dogged by scandals and trailed in polls, has gotten a lifeline from Elon Musk, who lives in Texas and has several businesses headquartered there. Musk spent at least $189.6 million as of late October to help Paxton get elected, part of a larger, roughly $366 million push to help elect Republicans around the country.

Talarico is on the Democratic ticket with state Rep. Gina Hinojosa, who has stayed within striking distance of GOP Gov. Greg Abbott, who is seeking a fourth term leading the state. The Cook Report shifted that race from "likely Republican" to "lean Republican" on Oct.1. 4) A big night for progressives?

The election poses a test for the liberal wing of the Democratic Party. Nowhere is that more evident than Michigan.

Abdul El-Sayed says he's a capitalist and he doesn't identify with the Democratic Socialists of America, though he has ties to the group and some of its most prominent figures. But he's seen as a proxy for the group, and his performance in the Michigan Senate race against former GOP Rep. Mike Rogers could have major implications for the ascendant left wing of the Democratic Party and candidates affiliated with DSA.

El-Sayed is a former public health official who emerged out of a bruising primary against Rep. Haley Stevens and state Sen. Mallory McMorrow. He has run on populist campaign promises, such as single-payer healthcare, raising taxes on billionaires and corporations, and tackling corruption, including by banning corporate PAC donations.

While El-Sayed has mobilized a base of young progressive voters, Republicans have attacked him as too radical, and some moderate Democrats warn that his winning could add legitimacy to the DSA movement and ultimately hurt the party.

"Democrats have an opportunity this cycle. They should not honor that opportunity by lurching to the far left, they should not misread their mandate if they hope to retain the inroads that they're making this cycle with Latino voters, with working-class voters who they have been hemorrhaging with cycle after cycle," said Lucas Holtz, a senior political advisor at Third Way, a center-left think tank.

In an unexpected development on Sunday, Stevens endorsed Rogers after a rift emerged between her and El-Sayed that centered on their opposing views on U.S. support for Israel. 5) A referendum on Trump?

Trump has dominated the Republican Party for the better part of a decade, but he's entering lame-duck territory on a low note and faces a blitz of congressional oversight and investigations if Democrats win the gavels in one or both chambers.

His handling of foreign policy, tariffs, the economy and immigration has drawn scrutiny, potentially dragging down Republican candidates.

Ahead of the election, a growing group of Republicans sought to distance themselves from the president. If a blue wave materializes and Republicans lose the House, Senate or both, some speculate he could shed even more supporters, as the party looks to a post-Trump world in 2028 and beyond.

But according to Brittany Martinez, executive director at Principles First and a former aide to then-House Speaker Kevin McCarthy, R-Calif., turning the page on Trump is not a given, even if Republicans lose.

"A big Republican loss would give more people in the party a reason to challenge Trump, but it wouldn't automatically give them the courage to do it," Martinez told CNBC. "The real test is whether Republicans acknowledge voters' dissatisfaction with his leadership or blame everyone else and carry on."