The weaknesses of the House Dems impeachment brief, George Mason U law professor FH Buckley on his new book on secession. RealClearPolitics.com's Susan Crabtree on the tale of two whistleblowers, Boomer dad vs. millennial dad...and how the former brought us Gulag Bernie, and National Association of Scholars' Peter Wood on textbooks, 1620 vs. 1619.