Sen. Pat Toomey's Supporters Insist He's Republican Despite Pres. Donald Trump's Late-Night Tweet

PITTSBURGH (KDKA) -- Over the weekend, U.S. Sen. Pat Toomey, a Pennsylvania Republican, called President Donald Trump's commutation of Roger Stone's sentence a "mistake."

That led to Pres. Trump to tweet that Toomey wasn't really a Republican.

On Friday night, the President commuted Stone's 40-month jail sentence for witness tampering and perjury.

The next day, U.S. Senator Mitt Romney, a Utah Republican, called it "unprecedented, historic corruption" by Pres. Trump. That was followed by a milder statement from Toomey, who called it a "mistake."

Pres. Trump reacted to both Republicans by tweeting that they were RINOs or Republicans in name only.

"Do RINO'S Pat Toomey & Mitt Romney have any problem with the fact that we caught Obama, Biden, & Company illegally spying on my campaign? Do they care if Comey, McCabe, Page & her lover, Peter S, the whole group, ran rampant, wild & unchecked - lying & leaking all the way? NO," Pres. Trump tweeted.

Toomey a RINO? That notion came as a surprise to some Pennsylvania Republicans.

"Senator Toomey has supported President Trump's top priority and his landmark legislation," Lawrence Tabas, chair of the Pennsylvania Republican Party, told KDKA political editor Jon Delano on Monday.

Toomey votes 88 percent of the time for Trump's agenda, reports the political website FiveThirtyEight, but he does disagree with Trump on some spending bills.

"This is much ado about nothing," says Sam DeMarco, chair of the Allegheny County Republican Party. "I don't think we agree 100 percent with anybody any of the time, including our spouses."

In his tweet, President Trump also claimed Toomey ignores FBI corruption and spying on the Trump campaign. Not true, say Toomey's defenders.

WATCH: KDKA's Jon Delano Has More With Lawrence Tabas And Sam DeMarco

"Senator Toomey has publicly supported the removal of James Comey as FBI director, and believes that all those that are responsible for this abuse of power should be held accountable," says DeMarco.

"I think the President will be reelected, and Senator Toomey will work closely with him over the next four years," said Tabas.

So why this tweet against Toomey?

"I think the president is extremely frustrated, and I think that's shown," says DeMarco.

KDKA reached out to both the White House and the Trump campaign. For the moment at least, they have no further comment.