THE PUBLIC MARVELED when Bill Weld dove into the Charles River in the summer of 1996. Now the two-time Massachusetts governor and former US attorney is plunging into an even more toxic stew.

About three months after re-registering with his old party, Weld on Patriot’s Day announced his Republican candidacy for president. His campaign launch video leans heavily on his record in Massachusetts and on President Donald Trump’s comments that have made the nation’s top office-holder a pariah among many fellow Republicans and virtually all Democrats.

So far at least, Trump’s campaign is giving short shrift to Big Red. Trump campaign national press secretary Kayleigh McEnany told CBS News they are not taking Weld’s campaign “seriously at all.”

Questions remain over how seriously Weld will take his endeavor. Weld in 2016 ran as the Libertarian Party’s vice presidential nominee, and his presidential exploratory bid earlier this year was a bare bones operation in many ways. Weld won two gubernatorial elections, but only completed one full term.

But in her interview McEnany also alluded to one of the main strategic drawbacks the Trump campaign could face if Weld can mount a serious challenge.

“We’re focused on the Democrats,” McEnany said.

One success for Weld, we can assume, would be distracting Trump enough and peeling off a sizable chunk of disaffected Republican voters so as to give whomever the Democrats choose as their nominee a better shot at winning in November 2020. While his party has changed, his opposition to Trump has been a constant.

Weld’s goal is to win the New Hampshire primary, and on Tuesday he visited three Granite State diners where he compared his campaign favorably to a “ferocious” fisher cat.

Taking on Trump from within the Republican party will be no walk in the park.

The Republican National Committee backs Trump, and there has been some question about whether Republicans will even hold primaries next year in some states to nominate their 2020 candidate. Trump is enormously popular within his party, and Massachusetts Republican Party chairman Jim Lyons skewered Weld as a traitor earlier this year when he announced his exploratory campaign.

“Even Benedict Arnold switched allegiances less often!” Lyons howled.

Howie Carr, one of Trump’s chief boosters in New England media, focused on Weld in today’s Boston Herald column, asking repeatedly whether Weld is an alcoholic. Trump had implied the same during his 2016 campaign.

One other big question for Weld is how his successors will respond to his candidacy. Four Republican governors, counting Acting Gov. Jane Swift, have followed Weld into the corner office since his 1990 win – and only one Democrat. Two of them – Utah Sen. Mitt Romney and Gov. Charlie Baker, a former Weld cabinet secretary – now hold statewide elected office and national platforms if they choose to use them. Both opposed Trump in 2016 but not so strongly that they endorsed his Democratic party opponent Hillary Clinton.

While Baker has clearly connected with Massachusetts voters – Republicans and Democrats – he has been aloof at times from his party nationally. He endorsed Chris Christie in 2016, and then appeared caught off guard when Christie dropped out and endorsed Trump before the Massachusetts primary.

Will either of them — or any other major figures in Republican politics — rally to Weld’s side? Today, Weld is alone.