WORCESTER, MA — U.S. Rep. Jim McGovern has come out in support of Vice President Kamala Harris’ presidential bid after President Joe Biden dropped out Sunday, signaling that Democrats in Massachusetts will broadly support her at the nominating convention in August.

McGovern came out early in support of Harris, saying in a Sunday evening tweet that he “wholeheartedly” endorses Harris.

“Throughout her career in public service she has shown an incredible ability to bring people together, take on the big banks & special interests, stand up for the underdog, & fight for what she believes in,” he said.

McGovern is a Democratic delegate who will be part of the nominating convention in Chicago beginning Aug. 19. No other potential Democratic presidential candidates had emerged as of Monday, but it’s possible Harris could face challengers from within her party.

By Monday morning, U.S. Rep. Katherine Clark — the most powerful Democrat from Massachusetts in Congress who serves as the minority whip — had endorsed Harris. U.S. Reps. Jake Auchincloss, Ayanna Pressley, Seth Moulton, Lori Trahan, Bill Keating and U.S. Sens. Elizabeth Warren and Ed Markey also backed Harris. Attorney General Andrea Campbell also endorsed Harris, but Gov. Maura Healey and U.S. Rep. Richard Neal, D-Pittsfield, hadn’t outright endorsed her as of Monday morning.

Most importantly, Biden endorsed Healey. His delegates are now free to vote for whomever they choose. It’s only the first item on a staggering political to-do list for her after Biden’s decision to exit the race, which she learned about on a Sunday morning call with the president. If she’s successful at locking up the nomination, she must also pick a running mate and pivot a massive political operation to boost her candidacy instead of Biden’s with just over 100 days until Election Day.

On Sunday afternoon, Biden’s campaign formally changed its name to Harris for President, reflecting that she is inheriting his political operation of more than 1,000 staffers and a war chest that stood at nearly $96 million at the end of June. It got bigger by Monday morning: Campaign spokesperson Lauren Hitt said Harris had raised $49.6 million in donations in the first 15 hours after Biden’s endorsement.

Harris spent much of Sunday surrounded by family and staff, making more than 100 calls to Democratic officials to line up their support for her candidacy, according to a person familiar with the matter who spoke on the condition of anonymity to discuss the effort. It comes as she tries to move her party past the painful, public wrangling that had defined the weeks since the Biden’s disastrous June 27 debate with Donald Trump.

The Associated Press contributed reporting to this story