Here are a dozen things we have learned in President Trump’s first 100 days.

1. Trump has had the worst beginning of any president since, oh, perhaps William Henry Harrison (who died a month after his inauguration). Trump has had no legislative triumphs, and he has by far the lowest public approval of any new president in polling history. Large majorities say he is not honest, does not keep promises and does not care about ordinary people.

2. Trump distinguishes himself in one area: incompetence. The debacle of the travel ban was followed by the collapse of the G.O.P. health care bill, and I doubt we’ll ever see passage of a tax reform package, a health bill or even a major infrastructure spending bill. Trump has made no trips abroad (at this juncture, Barack Obama had visited nine countries), and he has fewer than half as many nominees confirmed for senior positions as Obama did at this point.

3. New presidents typically grow into the job, but Trump remains a bully and a charlatan. In my career, I’ve never known a national politician as mendacious, ill informed, bombastic and dangerous as Trump. His tweets are as immature as ever, and The Washington Post calculates that he has issued 452 false or misleading claims since assuming office, churning them out at a rate of more than one every six hours around the clock (no wonder he seems so busy!).

4. The opposition to Trump has been ineffective in reaching Trump voters, and he remains deeply popular with his base. Only 2 percent of Trump voters say they regret their choice in November, and an ABC/Washington Post poll suggested that if 2016 voters filled out their ballots today, Trump would be elected by the popular vote as well as by the electoral vote. Even more people say that the Democratic Party is out of touch with ordinary voters than say the same of the Republican Party. Trump’s popularity among Republicans means that the liberal aim of removing Trump by impeachment or the 25th Amendment is probably fantasy — and all this should prompt some hard reflection among progressives.