Seismologists report that the chunks of granite falling from the Mount Rushmore National Memorial come from the laughter of Abraham Lincoln, George Washington, Thomas Jefferson and Theodore Roosevelt after they read a recent email blast from the National Republican Senatorial Committee. Donald Trump is “the greatest president in American history,” the NRSC’s fundraising missive declared. The group, whose purpose is electing Republicans to the Senate, isn’t known for having a staff of eminent historians. But that didn’t stop the NRSC from making the claim about Trump in an email urging people t…