GOP presidential front-runner Donald Trump has reportedly begun building an informal political kitchen cabinet of advisers — including former New York Mayor Rudy Giuliani — for his White House bid.Giuliani, who ran unsuccessfully for the GOP presidential nomination in 2008, tells The Washington Post he's among a group of New York-and Washington-based Republicans in regular touch with Trump, connecting his campaign with their own networks."We've been talking. Donald and me, Donald and a few other friends who know politics," Giuliani tells the Post."He calls to check things out or I'll call him to say, 'Donald, you're going too far' or, 'What you said was great' or maybe, 'Change it a bit.' It's nothing formal. It's kind of a running conversation."The former mayor says there's "an open line, him to me, me to him, him to others.""He is calling a lot of people, listening but doing what he thinks he needs to do," Giuliani tells the Post. "He listens respectfully, says he'll consider whatever it is you send him. Sometimes he uses what we send him, sometime he doesn't."Giuliani also gives Trump kudos on his understanding of complex policy issues, declaring, "You know, he is very good.""It's clear that he has an exceptionally good understanding of how the economy affects our foreign policy," Giuliani tells the newspaper."He understands what's happening with China, how they could stop North Korea in a heartbeat. This idea that he's only familiar with slogans, it's not accurate at all."Trump's growing network reminds Giuliani of one former President Ronald Reagan created in 1980, the Post reports."I think he could over perform in a general election similar to what Reagan did in 1980, bringing in new people," Giuliani says."He has that ability. On the other hand, I've told him when I've disagreed, telling him when I think he may be hurting himself — including Trump's blast at former President George W. Bush during the Feb. 13 Republican candidates' debate."I thank God that George W. Bush was president during 9/11," Giuliani tells the Post.