Three hot takes:
1. The lack of security at the Capitol was clearly a tactic. I'm not sure the Capitol Police are really at fault, though of course in retrospect it was a really bad mistake. During the BLM marches on the mall, there were fully fitted out infantry/police, 2 or 3 deep, on the Capitol steps. On Jan 6, very few police, and not wearing riot gear. The thought must have been that it would be better not to have a show of force, to avoid provoking violence.
The police had no way of knowing in advance that Trump was going to throw them under the bus, actually telling his supporters to go to the Capitol and (implicitly) mob it.
I do have a question about the counterfactual: Suppose there had been a substantial show of force, and the mob had attacked (more than a few of the rioters were armed). There would have been dozens of casualties, on both sides. Would that have been better?
For myself, the answer is yes. The symbol of the relatively easy takeover of the Capitol is very bad. But having 5 police and 20 rioters killed and wounded (say) would have been pretty bad also.
2. DJT made a speech at the rally yesterday. He said that being "weak" was bad, and now was the time for strength. Having the Capitol stormed by a mob, almost without resistance, and having the cops be sprayed with mace and beaten up, and having people breaking into secure areas and the offices of elected officials, is NOT strength.
The only way to make that strength is if you care only about Trump, and hate the U.S.
3. We are lucky that Trump is lazy, incompetent, and shallow. With a competent leader, capable of planning, yesterday could have been an actual coup. Imagine that instead of firing up the mob and then being surprised (I think) that they did something, Trump had in fact led the March to the Capitol. Imagine that he had quietly coordinated that march with even one dissident tank battalion. With 50 tanks, that march could have actually occupied the Capitol and held the Congress hostage.
Instead, Trump went back to the WH to watch TV, like he always does, unless he's playing golf. That's not what Lenin, Stalin, Mussolini, Hussein, or Putin would have done.
The best analogy is probably Mussolini's "March on Rome," where King Emmanuel likewise did not offer police or military opposition. It's very fortunate that Trump is not capable of carrying out a detailed plan. It could have been much, much worse, since it turns out that the Capitol was wide open for the taking.