Donations to the Clinton Foundation nose-dived last year amid Hillary Clinton’s presidential run, pay-to-play allegations, internal strife and a black mark from a charity watchdog. Contributions fell by 37 percent to $108 million, down from $172 million in 2014, according to the group’s latest tax filings. The cash plummeted as Hillary Clinton left the nonprofit in April 2015 after announcing her ill-fated candidacy. The foundation became a major issue in the race, with Donald Trump vowing to appoint a special prosecutor to investigate it. Whether that effort will go forward is not clear. Rep. Jason Chaffetz (R-Utah), head of the...