Former Massachusetts Gov. Bill Weld said the country is in grave peril, and he can no longer sit on the sidelines.

“Let the record reflect that I'm now in second place in the Republican primary,” he told the “Fox News Rundown” podcast Wednesday, discussing his decision to challenge Trump for the party nod in the 2020 race.

On Monday, he became the first Republican to challenge Trump in the party primaries. That makes Trump the first incumbent president since George H.W. Bush in 1992 to face a notable primary challenge.

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Fiscally conservative but socially liberal, Weld is known for an unconventional, at times quirky, political style and a long history of friction with the party he now aspires to represent.

Weld, 73, said in announcing his candidacy on Monday that “it is time to return to the principles of Lincoln — equality, dignity and opportunity for all.”

“There is no greater cause on earth than to preserve what truly makes America great. I am ready to lead that fight.”

Weld has said that Trump's “priorities are skewed toward promotion of himself rather than ... the good of the country.”

About the daunting challenges ahead, Weld said: “It's always uphill against an incumbent. And you know, I'm I think a poll I saw within the last few days had me at 8 percent nationally, which is where both Bernie Sanders and Donald Trump were at this stage four years ago.”

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While Trump’s overall approval ratings have been poor for much of his presidency, he remains popular with Republican voters. The Republican National Committee in January issued a nonbinding resolution to declare the party’s undivided support for Trump.

The Associated Press contributed to this report.