Sen. John McCain (R-Ariz.) said he'll think about having Sen. Joe Lieberman (I-Conn.) campaign for him.

McCain said Tuesday he hasn't thought of asking Lieberman to join him in Arizona as he faces a GOP primary challenge from former Rep. J.D. Hayworth. Lieberman famously endorsed McCain for president in 2008 — a decision that disappointed many Democrats -- and McCain recently reached out to his running mate, former Alaska Gov. Sarah Palin, to appear with him at events in Arizona.

"I haven't thought about it, but I'll think about it," McCain said. "He's a dear friend and I love to spend time with him."

Lieberman, who involves himself sparingly in primaries around the country, indicated he was wary of the idea, at least until after McCain's primary.

"He's in a primary now, so I don't know if I could help him," he said.

When asked about campaigning with McCain during the general election, Lieberman said, "I don't know."