Continuing the "Trump now a liability to the Republicans", the WSJ op-ed page calls Trump's action "impeachable" and suggests he should resign:

Donald Trump's Final Days - WSJ

This was an assault on the constitutional process of transferring power after an election. It was also an assault on the legislature from an executive sworn to uphold the laws of the United States. This goes beyond merely refusing to concede defeat. In our view it crosses a constitutional line that Mr. Trump hasn't previously crossed. It is impeachable.

If Mr. Trump wants to avoid a second impeachment, his best path would be to take personal responsibility and resign. This would be the cleanest solution since it would immediately turn presidential duties over to Mr. Pence. And it would give Mr. Trump agency, a la Richard Nixon, over his own fate.

Adding to several news outlets like USA Today, the WaPo and the Miami Herald.

Trump has finally realized he is now in danger and is scrambling to clean up the mess he has created.