(MILWAUKEE) - Mitt Romney is adding to his big lead in the race for convention delegates by sweeping Republican presidential primaries in Maryland, Wisconsin and the District of Columbia.
The former Massachusetts governor won at least 74 delegates in Tuesday's contests, with 21 delegates yet to be decided. Romney got all 16 delegates in the District of Columbia. He won at least 28 delegates in Maryland and at least 30 delegates in Wisconsin.
Nine delegates were yet to be decided in Maryland, and 12 were still undecided in Wisconsin.
Tuesday's contests marked the midway point in the race for convention delegates.
Romney leads the race for delegates with 646. His closest rival, Rick Santorum, has 272. It takes 1,144 delegates to win the GOP nomination for president.
Gingrich vows to stay in race
Republican Newt Gingrich says he isn't leaving the party's presidential race and is vowing to continue all the way to the nominating convention.
Gingrich said Tuesday he is committed to carrying the banner of bold conservative colors all the way to Tampa to ensure, in his words, "the Republican Party never abandons the timeless conservative principles."
With only two primary victories and rival Mitt Romney on pace to win the nomination in June - if not before - Gingrich faces an uphill fight. He lost all three of Tuesday's primaries, contests in Wisconsin, Maryland and the District of Columbia.
The former House speaker says Republicans cannot win with what he calls "an Etch A Sketch platform that shows no principle or backbone," a criticism of Romney's shifts on policy issues.
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