Venture capitalist and Marine veteran Brian Shortsleeve on Monday became the second Republican to officially line up for a chance to challenge Gov. Maura Healey in 2026.

Shortsleeve’s campaign launch video touts his time helping to lead the MBTA under former Gov. Charlie Baker. His tenure at the transit agency and its subsequent performance with Healey’s team at the helm are likely to become focal points as the race unfolds.

“A few years ago, the MBTA was falling apart. Governor Baker called me in,” Shortsleeve, a Barnstable resident, says in the video. “Talk about mission impossible, but I got to work, cut the waste, balanced the budget, modernized the system. We turned things around, until Gov. Healey took it back and broke the budget all over again.”

Shortsleeve was a Wellesley resident and commuter rail rider when he joined Baker’s team in 2015 as the T’s first chief administrator, after record snowfall battered the transportation system. He went on to serve as acting general manager and a member of the MBTA’s Fiscal and Management Control Board.

Shortsleeve’s campaign platform includes pledges to cut taxes and fees, and to tackle the migrant crisis that costs the state hundreds of millions of dollars annually in shelter expenses.

He also wants to repeal the MBTA Communities Act, the controversial law Baker signed that requires cities and towns to zone for denser housing near transit stations.

Shortsleeve’s campaign described the law as an “unfunded mandate that punishes towns and ignores infrastructure limits” and said he wants to “go back to the drawing board to develop a win-win solution to the housing crisis.”

Shortsleeve is the second Baker administration veteran to launch a gubernatorial bid this year, joining former Housing and Economic Development Secretary Mike Kennealy of Lexington. That dynamic could find the two candidates competing for the backing from the same pool of donors and big-name supporters while also trying to win over the broader GOP primary electorate.

“Massachusetts needs a manager to clean up Maura Healey’s mess,” Kennealy campaign manager Ben Hincher said in a statement. “When Brian Shortsleeve had his chance to lead, he mismanaged the MBTA and left it in just as big a mess as he found it. It’s hard to imagine exactly what he’s 'proud’ of.”

Steve Kerrigan, chair of the Massachusetts Democratic Party, jabbed at both Shortsleeve’s politics — Shortsleeve supported Florida Gov. Ron DeSantis in his White House bid and told the Boston Herald he ultimately voted for President Donald Trump — and his time atop the MBTA.

“The people of Massachusetts don’t want to hire the guy who ran the T into the ground to run their entire state,” Kerrigan said in a statement. “Slowzone Shortsleeve left behind an MBTA that was mismanaged and riddled with broken down cars and tracks. Now, under Governor Maura Healey and GM Phil Eng, the MBTA is slow zone free for the first time in years.”

A February poll from UMass Amherst, conducted before either Kennealy or Shortsleeve formally announced their campaigns, gave Healey a solid lead against either opponent. Forty percent of respondents picked Healey over Kennealy and 44% against Shortsleeve, though nearly 40% were undecided in each hypothetical matchup.