Now that President Donald Trump doesn’t have Shepard Smith to kick around at Fox News any longer, he’s attacking “Fox News Sunday” host Chris Wallace.

Wallace is one of the few remaining news hosts at Fox who routinely presents a balanced perspective, and who often challenges Trump’s policies and statements. Smith abruptly resigned from Fox on Friday after being repeatedly criticized by Trump.

Following Wallace’s program Sunday, Trump fired off a tweet demanding that “somebody please explain to Chris Wallace” that Trump’s July phone call with Ukraine’s president “was a congenial & good one.” In the call, now the focus of an impeachment inquiry, Trump pressed the Ukrainian leader to investigate his political rival Joe Biden and his son — while withholding military aid from the nation.