Trump’s convincing wins over Ohio Governor John Kasich, Ted Cruz, a U.S. senator from Texas, and Marco Rubio, a U.S. senator from Florida, increased the pressure on the party’s anti-Trump forces to find a way to stop his march to the nomination ahead of several key contests next week.

Trump had split four nominating contests on Saturday with the conservative Cruz, who had positioned himself as the prime alternative to the brash New York billionaire in the race to be the party’s candidate in the Nov. 8 election.

The win in Michigan, the night’s biggest prize, could set Trump up for a potentially decisive day of voting on March 15, when the delegate-rich states of Ohio, Florida, Illinois, Missouri and North Carolina cast ballots.

The Republican contests in Florida and Ohio award all the state’s delegates to the winner. If Trump, 69, could sweep those two states and pile up delegates elsewhere next week, it could knock home-state favorites Rubio and Kasich out of the race and make it tough for Cruz to catch him.

Rubio, 44, is the favorite of a Republican establishment alarmed by Trump’s controversial proposals and anxious about Cruz’s uncompromising conservatism, lagged in Michigan polls and needs a win in his home state next week to keep his campaign alive.

Republicans were also voting on Tuesday in Idaho and Hawaii.

Democratic front-runner Hillary Clinton also won in Mississippi, helped by a strong showing with African-American voters, who make up more than half of the Democratic electorate. Exit polls showed Clinton winning nine of every 10 black voters.

Clinton and rival Bernie Sanders were locked in a tight race in Michigan with about 30 percent of the votes counted.

In Mississippi, exit polls showed Trump won among voters who described themselves as evangelicals, with 45 percent compared with 39 percent for Cruz. Trump also won voters who said they wanted a president from outside the political establishment and those who described themselves as “angry” about how the federal government is working.

Cruz won voters who called themselves “dissatisfied, but not angry,” edging Trump with 37 percent to the billionaire’s 34 percent.

(Additional reporting by Emily Stephenson, Alana Wise, Amanda Becker in Washington; Editing by Peter Cooney, Frances Kerry and Jonathan Oatis)