Mitt Romney expanded his delegate lead significantly on Tuesday, taking at least 83 delegates from Wisconsin, Maryland and the District of Columbia and reinforcing that he is on a clear path for the GOP presidential nomination.

Romney has expanded his delegate lead over Santorum to 655 to 278, according to the most recent AP projections. (For all the numbers, see the Post’s delegate tracker.)

The 83 delegates Romney won for sure makes Tuesday his second-biggest single-day delegate haul of the GOP primary season.

The former Massachusetts governor now has 57 percent of the delegates he needs to clinch the nomination. He only needs to win 42 percent of the remaining delegates in order to seal the victory.

Santorum, meanwhile, would have to win 75 percent of the remaining delegates to win the nomination before the GOP convention. But he seems to be banking on an open convention instead.

Romney took home all 53 delegates at stake in Maryland and the District of Columbia, by virtue of his big wins in those two contests. In Wisconsin he won the statewide vote and at least four congressional districts, which award three delegates apiece to the winner.

Santorum won at least two districts in Wisconsin, with two other districts yet to be determined.

Romney also is expected to do well in the next set of primaries, scheduled for April 24 in the East Coast states of Connecticut, Delaware, New York, Rhode Island and Santorum’s home state of Pennsylvania.