BIRMINGHAM, Ala. — VoteVets, the political action committee that backs liberal veterans running for office, has endorsed Pete Buttigieg for president, the first major organization to support him.
The endorsement brings Mr. Buttigieg, the mayor of South Bend, Ind., and a former Navy officer who served in Afghanistan, new defenders in a 2020 Democratic presidential contest that has seen better known candidates drop out as polling shows early-state voters coalescing around the four leading candidates.

Jon Soltz, the co-founder and chairman of VoteVets, said that other campaigns weren’t taking on Mr. Buttigieg directly but that they were using opposition research to try and “hold back his momentum.”He added: “They haven’t really been able to do it and now it’s a question of what is Pete’s coalition? We feel it’s important to jump into the breach and let people know that VoteVets is the start of that coalition.” VoteVets will make a maximum contribution to the Buttigieg campaign, Mr. Soltz said, but its most significant support may come from the organization’s super PAC and its 501(c)(4) arm, which can engage in issue advocacy and is not required to disclose its donors.

The VoteVets endorsement for Mr. Buttigieg means that of the four leading candidates, Senator Elizabeth Warren of Massachusetts is the only one without an outside organization poised to purchase TV ads on her behalf. Unite the Country plans to soon start running ads for former Vice President Joseph R. Biden Jr. and Senator Bernie Sanders of Vermont has the National Nurses United’s super PAC, which spent $5 million backing him in 2016 and has yet to buy TV time this cycle.

A super PAC backing Senator Kamala Harris of California was set to begin advertisements in Iowa before she dropped out of the race on Tuesday, and United We Win, a super PAC supporting Senator Cory Booker of New Jersey, launched in November with the goal of helping Mr. Booker qualify for the December debate. The group has spent $1 million and is funding a TV ad in Iowa that attacks Mr. Buttigieg.

VoteVets, the nation’s largest political action committee that supports liberal veterans for public office, announced its presidential endorsement for South Bend, Ind., Mayor Pete Buttigieg Wednesday. The endorsement, the first in the progressive group’s history, could serve as another boost for Buttigieg, a former Navy officer who served in Afghanistan. The announcement comes as polling shows a fluid race in early voting states with the Indiana Democrat at or near the top in Iowa and New Hampshire.

“The number one priority has to be beating Donald Trump. In the 13 years VoteVets has been in existence, we have come to see one thing repeated time after time: Veterans can win voters in the purple and red areas of the country that other Democrats cannot,” said Jon Soltz, an Iraq War veteran and chairman of VoteVets, referring to several veterans who won tight races in the 2018 midterms. We need a candidate who will win. Bar none, Pete gives us the best shot at doing just that. It is time to rally around him, and stop the walking, talking national security threat that is Donald Trump.”

“Pete is also someone who has the experience, as a war veteran, to be an exemplary Commander in Chief, because he understands and has experienced the unique global security challenges we face right now, and he has the personal understanding of our veterans’ needs. His executive experience as Mayor, and his proven ability to think outside of the box to revitalize communities is exactly what veterans and all Americans need in a president right now. We could not be more proud to stand with him, and eagerly await the day when this new generation of American leadership is sworn in,” added Kate Hoit, Iraq War Veteran and Senior Adviser to VoteVets.