Mitt Romney won the Maryland Republican primary Tuesday, CNN projects, a victory that bumps him over the halfway mark to getting the 1,144 delegates needed to win the nomination. With less than 1 percent of precincts reporting, Romney has more than 50 percent of the vote. He's expected to win the Washington, D.C. primary, too, while Wisconsin is Rick Santorum's best shot to win a state tonight. Polls close in Wisconsin at 9p.m. eastern time. Update 8:52p.m.: CNN projects Romney wins Washington, D.C.

According to exit polls, Romney won everyone over 45, and Santorum won everyone younger. Though Romney won both men and women, the gender gap was significant -- and women went more for Santorum. Romney won men by 24 percentage points but women by 19 percentage points. That's mostly because lots of guys, 15 percent, voted for Ron Paul, while only 5 percent of women did. Romney even won among conservatives -- and tied among very conservative voters.

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Elspeth Reeve