Republican donors with links to several presidential candidates - as well as a prominent GOP operative - are pooling their resources in a new effort to go after Donald Trump and keep the party's presidential front-runner from winning the nomination. The most recent bid is a reported "guerrilla campaign" led by a group called Trump Card LLC and run by Liz Mair, former communications official for the Republican National Committee. The group's goal, according to The Wall Street Journal, is to collect money from anonymous donors to "defeat and destroy" Trump, who has essentially led the GOP presidential field since...