Washington (CNN) Former Massachusetts Gov. Bill Weld said he's launching a presidential exploratory committee to run in 2020 as a Republican.

"I hope to see the Republican Party assume once again the mantle of being the party of Lincoln. It upsets me that our energies as a society are being sapped by the President's culture of divisiveness in Washington," he said Friday in New Hampshire, adding later, "Because of the many concerns I've talked about today, I've established an exploratory committee ... as a Republican in the 2020 election."

Speaking at the "Politics & Eggs" breakfast in Bedford, New Hampshire, Weld called Donald Trump a "schoolyard bully," "unstable" and "a president whose priorities are skewed to the promotion of himself rather than toward the good of the country."

Though a number of Democratic candidates have joined the 2020 race in hopes of ultimately facing off against Trump in the general election, Weld is the first potential primary challenger to the President.

to take down Trump. History shows that presidents generally only face serious primary challenges when their approval rating within their own party is at 75% or below. Trump is currently far above this threshold. Weld will face an uphill battle in his efforts to take down Trump. History shows that presidents generally only face serious primary challenges when their approval rating within their own party is at 75% or below. Trump is currently far above this threshold.