Addressing a huge crowd of loyal supporters south of the White House, President Trump declared that he will never concede to Joe Biden and attacked "weak Republicans" — calling out "the Liz Cheneys of the world" — for failing to support his efforts to overturn the results of the election.

Why it matters: It's a new escalation in Trump's war against the GOP, which has pitted Senate Majority Leader Mitch McConnell and other mainstream Republicans against the most popular figure in the party. Cheney is a member of House Republican leadership, meaning that Minority Leader Kevin McCarthy will likely be forced to respond.

The big picture: It was in many ways a traditional Trump rally, but unusual in that it came hours before Congress is set to meet in a joint session to certify President-elect Joe Biden's Electoral College victory, officially sealing off any path to a second Trump term.

Zoom in: Trump, as he has done several times over the past few days, sought to exert pressure on Vice President Mike Pence, who will preside over Congress as it counts the electoral votes.

• "If Mike Pence does the right thing we win the election," Trump falsely claimed. Pence has no constitutional authority to block Congress from certifying the Electoral College.
• Trump also attacked McConnell and other Republicans who have resisted doomed efforts to block certification of Biden's victory.
• In a speech before the president arrived, Donald Trump Jr. threatened to campaign against any Republican in Congress who doesn't object to Wednesday's certification.

Between the lines: Trump has never had any affinity for the institutional party. He has always seen it as the Trump Party. And now he plans to use his popularity with the base to inflict as much pain as possible on elected Republicans who don’t perform this final act of subservience.

• Nobody will be spared — not even Pence, the man who obediently and loyally served as his vice president for four years.
• Trump knows he is the most popular Republican in the country, and that his base will stand by him no matter what. It’s the reason he was able to wield total control over the party for the last four years, and he doesn’t plan on releasing his grip on them anytime soon.