In his first 100 days, President Donald Trump has exerted his power on a scale with no easy historical comparison.

Lisa Mascaro, congressional correspondent for The Associated Press, has been covering Congress since 2010 and is waist-deep in the current, extraordinary saga. So the challenge that’s being mounted comes from about a dozen Republican senators — I think we’re up to 13 now — and as many as 100 House Republicans. Laws have been enacted to govern this process — and a joint session of Congress is sort of the final confirmation. The states confirm the results and the states determine the electors and then send that tally up to Washington. A number of House Republicans will challenge that.