[Source: Reuters]

Donald Trump swept Republican presidential nominating contests in Virginia, North Carolina, Oklahoma and Tennessee on Tuesday, Edison Research projected, as he sought to force rival Nikki Haley from the race on the primary calendar’s biggest day and set up a rematch with Democratic President Joe Biden.

Voters in 15 states and one U.S. territory were casting ballots for presidential nominees on Super Tuesday, with polls scheduled to close throughout the evening until Alaska wraps up the day at midnight EST (0500 on Wednesday GMT).

Immigration and the economy are leading concerns for voters in both parties, Edison exit polls in California, North Carolina and Virginia showed.

A majority of Republican voters in those states said they backed deporting illegal immigrants. Trump, who frequently denigrates migrants, has promised to mount the largest deportation effort in U.S. history if elected.

Katherine Meredith, a 65-year-old homemaker, voted for Trump in California’s Huntington Beach, which includes a significant Trump base despite California’s strong Democratic leanings.

“The border is a complete catastrophe,” Meredith said.

Biden was expected to sail through the Democratic contests, though activists opposed to his strong support of Israel called on Muslim Americans and progressives to cast “uncommitted” protest votes in Minnesota as they did before in Michigan.

The president easily won in Iowa, North Carolina, Virginia, Oklahoma and Tennessee, Edison projected.

Trump, who has dominated the Republican campaign despite a litany of criminal charges against him, has won all but one of the contests so far, winnowing a sprawling Republican field of candidates down to two.

While Trump cannot win enough delegates, opens new tab to formally clinch the nomination on Tuesday, another commanding performance would further pressure Haley, a former U.N. ambassador under Trump and a former South Carolina governor, to drop her long-shot bid.

Virginia had been among the states that Haley’s advisers had circled as an opportunity for a potential upset because of higher proportions of the wealthy, college-educated voters who tend to back her over Trump.

The day’s contests will award more than one-third of Republican delegates – and more than 70% of the number needed to secure the nomination.