The Republicans in the House who voted not to impeach, and the senators who voted not to convict, voted to accept that kind of mob attack as a normal part of their political lives. They voted for tyranny—not over the country as a whole, but over themselves, personally. They voted to live in fear of Trump and Trump’s mobs.
The impeachment vote was their chance to remove Trump’s malignant influence, standing up to a potential backlash from the voters this one time, but barring Trump from future office and ending his political career.
They couldn’t do it. By caving to the fear of temporary anger from their voters, many of whom continue to support Donald Trump, they will now live in fear for the rest of their political careers.