“Donald Trump’s endorsement remains the most valuable asset in GOP primaries. But after the president, it’s Charlie Kirk, the conservative activist and Turning Point USA leader who was killed on a Utah college campus last September,” Politico reports.“Candidates across the country, from Kentucky to Iowa to Arizona, are promoting their endorsements from Kirk’s organization, hoping to use it to appeal to the swath of young, mostly male, voters that he influenced and brought to the Republican Party in recent years.”