Presumptive Republican presidential nominee Mitt Romney is refusing to even utter George W. Bush's name after the former president endorsed him in an elevator on Tuesday.

"I'm for Mitt Romney," Bush had blurted out to ABC News on Tuesday as the doors of the elevator closed on him in Washington, DC where he was giving a speech on human rights.

Speaking to a crowd of supporters in St. Petersburg, Florida on Wednesday, Romney would only refer to Bush as President Barack Obama's "predecessor."

"[Obama] was very critical of his predecessor for the debts the predecessor put in place," Romney remarked. "It sure is true that you can't blame one party or the other for all the debts this country has because both parties, in my opinion, have spent too much and borrowed too much."

"But he was very critical of his predecessor because the predecessor put together four trillion dollars of debt over eight years," the former Massachusetts governor added.

The candidate later returned to the "predecessor" line again: "I find it incomprehensible that a president could come to office and call his predecessor's record irresponsible and unpatriotic, and then do almost nothing to fix it."

In a statement to CNN on Tuesday, Romney spokeswoman Andrea Saul "welcomed" the endorsement but also refused to mention Bush by name.

"We welcome the president's support, as we welcomed his father's," Saul said.

Watch the video below from CNN, broadcast May 15, 2012.

(h/t: Talking Points Memo)