COLUMBIA, S.C. (AP) — The long and occasionally quixotic relationship between Donald Trump and Lindsey Graham has again turned negative after the South Carolina senator criticized the former president for refusing to support a federal abortion ban.

Trump repeatedly disparaged Graham on his social media site and said he regretted endorsing the senator during his last reelection campaign. Graham, a staunch abortion opponent who has pushed for a national ban, did not back down from his criticism, saying Trump’s view was an “error.”

But some observers of the Trump-Graham dynamic think both Republicans benefit from their public strife.

For Trump, they say, creating public distance from anti-abortion advocates might help him blunt President Joe Biden’s attacks on an issue that Democrats have long credited for electoral victories since the U.S. Supreme Court, with three justices Trump nominated, overturned Roe v. Wade. Graham, meanwhile, gets to burnish his conservative bona fides against years of home-state criticism that he is too liberal.