The US elected a criminal to office and now his mobster impression with regard to Ukraine is finally leading to the first steps to removing him from office. To him, the truth is whatever he wants it to be at any moment.
Boris Johnson was elected by a majority of a small group of Conservative activists after Theresa May's resignation as Prime minister. Before Johnson entered politics, he was a "journalist" in Brussels who specialized in telling lies about the EU. He prorogued Parliament unlawfully so he could effect a hard Brexit opposed by most Britons and Members of Parliament.
What do they have in common? Both are supported by nativists who are losers from globalization. The nativism overlaps with bigotry.
How do they retain political support? Trump has used his supporters to take over the Republican party, abetted by politicians who have put ambition ahead of country. Johnson is benefiting from the first -past-the-post electoral system when there are more than 2 viable parties. The Liberal Democrats won the most British MEP seats using proportional representation.
Both are stressing their nations' constitutions, to say the least. How do these nations recover?