Republican presidential candidate Mitt Romney moved well past the halfway point in the delegate count for the GOP nomination by winning three more primaries Tuesday.
His position as the Republican front-runner is now very solid, and it would take a political miracle for main rival Rick Santorum or anyone else to overtake him.
Romney emerged with a commanding lead of 655 delegates out of the 1,144 needed for the nomination. Former Pennsylvania Senator Santorum has 278 delegates; former House Speaker Newt Gingrich has 135, and Rep. Ron Paul of Texas has 51, according to the Associated Press.
Romney, the former governor of Massachusetts, won the key battleground state of Wisconsin Tuesday with 42.5 percent of the vote to Santorum's 37.7 percent. Romney won Maryland over Santorum, 48.8 percent to 29.2 percent. He won the District of Columbia with 70.2 percent; Santorum didn't qualify for the ballot there.
Romney needs to win 40 percent of the delegates yet to be chosen and Santorum needs more than 70 percent.
The next tests come April 24 with primaries in Connecticut, Delaware, New York, Pennsylvania, and Rhode Island. Romney is favored in all those states except Pennsylvania, Santorum's home state, but even there Romney is gaining in the opinion polls.