Pierce Bush, the grandson of former President George H.W. Bush, announced his candidacy Monday for a congressional seat in Texas, becoming the latest member of his famous Republican family to enter politics. But his first run for office won’t be easy. Bush joins one of the nation’s most crowded congressional races of 2020 in his bid to replace Republican Rep. Pete Olson, who is retiring from his suburban Houston district that Democrats nearly flipped last year and are aggressively targeting again.