Boston lawyer Jim C. King announced on Wednesday afternoon that he would bow out of the contest for the Democratic nomination for U.S. Senate, ending a campaign that struggled from its start to mount any serious challenge to frontrunner Elizabeth Warren.

King’s withdrawal leaves Harvard Law School professor Warren and immigration attorney Marisa DeFranco as the only two remaining Democrats vying to represent their party against Republican incumbent Scott Brown in November. Warren has been considered by most political analysts to be the clear frontrunner in the Democratic race since she entered it last fall.

King’s campaign released a statement yesterday afternoon that said after much thought, King had decided his campaign was no longer benefiting his party or the Massachusetts electorate.

“The review has also made clear that the most effective way to achieve our goals has changed,” King wrote in the statement. “Now, we need to give Elizabeth Warren our support to beat Scott Brown in November.”