WASHINGTON (News Nation) — Democrats could take a step toward taking control of the U.S. Senate from Republicans on Tuesday when voters in Maine, Texas and Alabama cast ballots in nominating contests.

Maine Democrats pick a challenger to Susan Collins; Texas Democrats choose who will go up against Republican Senator John Cornyn in a Republican-leaning state; and Alabama Republicans pick a candidate to take on Doug Jones.

Democrats would need to pick up four seats in the 100-member chamber for a majority if President Donald Trump is re-elected, or three if presumptive Democratic nominee Joe Biden wins the White House, giving the party a tie-breaking Senate vote.

TOP DEMOCRATIC OPPORTUNITY

Democrats see Collins’ Senate seat representing Maine as one of their top pick-up opportunities. Democrat Sara Gideon, the speaker of the Maine House of Representatives, has been leading Collins by a few percentage points in recent opinion polls even before Tuesday’s primary between Gideon and two more left-wing Democrats, Betsy Sweet and Bre Kidman.

Collins is a moderate Republican first elected in 1996 who has long enjoyed a reputation for bipartisanship in a state with many independent voters. Her support eroded after she sided with Trump in several votes, including backing his Supreme Court nominee Brett Kavanaugh in 2018.

Collins’ vote for Kavanaugh served to “enrage many Mainers, and it’s caused a different reaction to Collins than there ever really has been before,” said Mark Brewer, political science professor at the University of Maine.

TEXAS TANGLE

In Texas, there is a Senate runoff between Air Force veteran MJ Hegar, who narrowly lost a race for a House seat in 2018, and state Sen. Royce West. If West wins, he would become Texas’s first Black U.S. senator.

For now, both remain underdogs against Republican Sen. John Cornyn, a three-term Senate veteran who is among the top 10 Senate candidates in terms of money raised, according to Federal Election Commission data.

The voting in all three states was delayed by the coronavirus pandemic.

DEMOCRATS PLAY DEFENSE IN ALABAMA

In Republican stronghold Alabama, Republicans will pick between Jeff Sessions – a former U.S. attorney general fired by Trump who now wants his old Senate job back – or political newcomer Tommy Tuberville, a former Auburn University football coach endorsed by Trump.

One of the two will go against incumbent Sen. Doug Jones, who has served in the Senate since 2018.

In a 2017 special election, Jones became the first Democrat to win a Senate seat from Alabama in a quarter century after defeating Roy Moore, whose campaign was derailed by accusations of sexual misconduct with teenage girls.