Donald Trump stops pretending the GOP is united and declares war on Paul Ryan

Grand Old Party's over!

Republican presidential nominee Donald Trump socked House Speaker Paul Ryan on Twitter Monday in retribution for Ryan's refusal to campaign for him.

The embattled Trump, under bipartisan siege after a bombshell tape of the nominee denigrating women emerged, snarled that the top GOP lawmaker "should spend more time on balancing the budget, jobs and illegal immigration and not waste his time on fighting [the] Republican nominee."

Trump threw down the virtual gauntlet, ripping the party's internal rifts wide open a day after being called out during the second presidential debate on Monday against Hillary Clinton for his widely denounced remarks.

Ryan reportedly told fellow Republicans in a conference call that he won't stand by his party's man after leaked Access Hollywood tapes from 2005 emerged, in which Trump said his star status gave him the ability to do anything he liked to women, including "grab them by the pussy."

The Wisconsin Republican and 2012 vice presidential nominee disinvited Trump from a joint appearance immediately after the Washington Post published the tapes.

Ryan has not gone so far as to say he won't support Trump against Clinton.

The day the Washington Post broke the story on the leaked tapes on Friday, Ryan cheerfully tweeted about hanging out with Sen. Rob Portman of Ohio.

The next day, Portman publicly disavowed his support for the controversial GOP nominee, saying he couldn't support Trump's remarks and would be voting for Trump's running mate, Mike Pence, instead.

Ryan, according to Politico, told House Republicans on the conference call that he's focusing on maintaining GOP control of the chamber and that they should make up their own minds about sticking with Trump or ditching him.

Trump has always run against the party establishment, so ostensibly, the Ryan dis could bolster his outside-the-Beltway sales pitch against insider Clinton.

At the same time, Trump's latest scandals have not helped him build the support he desperately needs among independent and undecided voters, and losing more surrogates within the GOP could damage his chances even further.