(CNN) — Mitt Romney will win Tuesday’s Wisconsin, Maryland and District of Columbia Republican presidential primaries, CNN projects, putting him past the halfway point for delegates needed to win the nomination.
The former Massachusetts governor is expected to take the majority of Maryland’s 37 delegates — he’ll win 13 winner-take-all delegates, and the rest are to be awarded proportionally, based on the outcome in the state’s eight districts.
Romney receives all the District of Columbia’s 16 delegates and many of Wisconsin’s 42 delegates.
The wins put Romney past the halfway mark to the 1,144 delegates needed to clinch the nomination and add to a wide delegate lead that he holds over the other major GOP presidential candidates, according to CNN estimates.
Romney received 51% of the vote in Maryland, according to early results on the State Board of Elections website, with Rick Santorum receiving 28%.
In the District of Columbia, Romney charged to a strong early lead, with 65% of the tally, according to very early results on the Board of Elections & Ethics website.
The Wisconsin race — where pre-Tuesday polls showed Romney with a single-digit lead over Santorum — might have been Santorum’s final chance to slow Romney’s march toward the GOP nomination.
Santorum told supporters Tuesday night he would continue to fight.
“Pennsylvania and half of the other people in this country have yet to be heard. And we’re going to go out and campaign here and across the nation to make sure their voices are heard in the next few months,” he said.
Santorum was not in the ballot in the District of Columbia.
Going into Tuesday, Romney had 571 delegates, according to CNN’s estimate. That’s more than twice the 264 delegates Santorum holds. Former House Speaker Newt Gingrich and Texas Rep. Ron Paul trail well back.
President Barack Obama, meanwhile, clinched the Democratic presidential nomination Tuesday with primary wins in Maryland and the District of Columbia, CNN projected. Unlike the Republicans, Obama faces no serious opposition in his race.
Speaking at a restaurant in Waukesha, Wisconsin, Romney suggested Obama wants to duck responsibility “for what’s happened in this country,” saying the president should get full credit or blame for “what’s happened in this economy, and what’s happened to gasoline prices under his watch.”
“It is time to have somebody who will take responsibility, and if I am president, I will not only get things right again, I will take full responsibility for my errors and make sure that people understand we have a president in the White House again where the buck will stop at his desk,” Romney said.
Later Tuesday, Obama mentioned Romney by name in a speech for the first time this year, while slamming a House-passed budget proposal that Romney has embraced.
Obama, speaking at a media luncheon in Washington, said the plan, which would lower tax rates and cut spending while reforming the Medicare and Medicaid government-run health care programs, was “thinly veiled Social Darwinism” and “antithetical to our entire history as a land of opportunity and upward mobility for everyone who’s willing to work for it.”
“One of my political opponents, Gov. Romney, has said that he hoped a similar version of this plan from last year would be introduced on day one of his presidency,” Obama said. “He said that he’s very supportive of this new budget and he even called it marvelous, which is a word you don’t often hear when it comes to describing a budget.”
Romney responded, in an interview with Milwaukee radio station WTMJ, that Obama is engaging “in the most incendiary rhetoric he can find out of an attempt to ignore the fact that we can’t keep on spending a trillion dollars more than we take in every year.”
After Tuesday, there are three weeks before five more states vote on April 24.
Romney appears to be the favorite in four: New York, Connecticut, Rhode Island and Delaware.
The fifth, Pennsylvania, is Santorum’s home state, but polls show his once-large lead there has disappeared.
CNN’s Tom Cohen contributed to this report.