Commentary Political “progressives” have intensified their attack on the U.S. Constitution. This is the fourth in a series of essays showing why their principal charges are false. The first essay answered the charge that the Constitution discriminated against women. As that essay shows, the Constitution is gender-neutral. The second essay rebutted the claim that the three-fifths compromise was motivated by racism. Actually, the compromise arose out of a negative economic assessment of slavery. The third essay responded to the assertion that the Constitution was designed to protect slavery. This column addresses “progressive” attacks on the institution of the U.S. Senate. The more extreme critics, such as the author of a 2018 GQ article, argue that we should abolish the Senate entirely and reduce Congress to a single chamber. But the dangers of unicameralism are too widely understood for this idea to have much traction. What James Madison wrote in 1788 …