Massachusetts Democrat Seth Moulton, who ran on a centrist, pro-military platform that never ignited the Democratic base, on Friday became the fourth Democratic presidential candidate to drop out of the race.

During his brief bid, Moulton, an Iraq veteran and former Marine infantry officer, focused primarily on foreign policy and national security. He defined himself as one of the more moderate candidates in a field that now numbers 21.

[Seth Moulton makes case that good foreign policy will beat Trump]

In remarks prepared for a speech to the Democratic National Committee’s summer meeting in San Francisco the third-term Democratic congressman, said he’ll run for reelection instead in 2020, and will devote his efforts to campaigning for the winner of the party’s nomination in 2020. Moulton, 40, also will relaunch his political action committee, Serve America, which focuses on military and veterans-related issues.

He did not endorse any of his fellow Democrats in an advance version of his speech.

Moulton joins Washington Gov. Jay Inslee in dropping out this week. Former Colorado Gov. Hickenlooper dropped out last week and Rep. Eric Swalwell of California dropped out in July. Hickenlooper will run for Senate in Colorado and Inslee and Swalwell will run for reelection.

Moulton, who entered the race in April, had failed to qualify for the Democratic primary debates in June and July. He ran so low in the polls that he was not even listed among the 13 Democratic candidates on Real Clear Politics. Earlier polls put him below 1 percent.

Moulton raised $1.9 million for his presidential bid between his declaration of candidacy and June 30. He had $724,000 in his campaign account as of June 30.

A handful of Democrats have considered running for his seat, including former Rep. John Tierney, who Moulton defeated in the 2014 primary. Only Jamie Zahlaway Belsito has filed documents with the Federal Election Commission.

Moulton was one of a handful of House Democrats critical of House Speaker Nancy Pelosi’s bid for speaker in 2018. An ally in that criticism, Ohio Democrat Tim Ryan, remains in the race.

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