Conservative radio giant Rush Limbaugh explained that he will not be making a formal endorsement of presumptive Republican nominee Donald Trump.

"In the words of a famous and well-known politician, what difference does it make now?" Limbaugh said on his show Monday, referring to an oft-quoted line by Hillary Clinton.

"I can't believe you think it matters now. ... I think it's a moot point now," Limbaugh told a caller who pleaded with him to declare his support for Trump. "Look, I've never endorsed in primaries, I've never made it a big deal. I've always tried to downplay it, to boot. I don't live under any delusions here that people are going to make up their minds on these serious things just because I happen to tell people who I'm for."

Trump is certain to be the GOP nominee, since all of his rivals withdrew from the race. The primaries are still ongoing state by state, however, until he finally locks up the required 1,237 delegates.

Read more on WashingtonExaminer.com