(CNN)– Former New York Mayor Rudy Giuliani joined the choir of ardent Hillary Clinton supporters Tuesday night– asking why Barack Obama passed up the New York senator for his number two spot.
"I just think that they made a big mistake in the choice that they made," Giuliani told a CNN panel at the Democratic National Convention. "It's a no-brainer. [Hillary Clinton] got 18 million votes, Joe [Biden] got 9,000 votes...The normal political thing to do in terms of the best decision to make to win would have been to pick Hillary Clinton," Giuliani said urging the presumptive Democratic nominee to give an explanation to unhappy Democrats.
Giuliani has been an outspoken supporter of the presumptive Republican nominee John McCain since abandoning his own presidential bid - emphasizing the Arizona senator's talking points on various political broadcasts.
Last week, during his first conference call as a surrogate for McCain, the former New York mayor had a difficult time when the subject veered away from the intended foreign policy talk. Giuliani accused Daniel Kurtzer, an Obama adviser and former U.S. ambassador to Israel of engaging in a freelance “mission” to Syria - accusations at which the Obama campaign quickly fired back.
Asked Tuesday night if he would draw contrast between the two parties during his keynote address next week at the Republican National Convention, Giuliani said you can expect him to do exactly that.
"I'm sure there will be comparisons," Giuliani said. The choice is between "John McCain who has tremendous experience who has worked on both sides of the aisle, against a senator from Illinois [who is] one of the least-experienced candidates we ever had for president."
Giuliani is expected to be part of a news conference Wednesday, during the Democratic National Convention to discuss "why Barack Obama is wrong on national security," according to a media advisory.