The relationship between Donald Trump and Lindsey Graham has again turned negative after the South Carolina senator criticized Trump for refusing to support a federal abortion ban. Trump disparaged Graham on his social media site and said he regretted endorsing the senator during his last reelection campaign. Graham is a staunch abortion opponent who has pushed for a national ban in the Senate and he didn't back down from his criticism, saying Trump’s view was an “error.” But some observers of the Trump-Graham dynamic think both Republicans may actually benefit from their public strife.