On the eve of CPAC, former Gov. Jim Gilmore is charging hard at the three leading Republican candidates for president. Gilmore previewed his message yesterday during a meeting with bloggers at The Heritage Foundation and will likely repeat parts of it during multiple appearances at CPAC later this week.

With John McCain, Rudy Giuliani and Mitt Romney (not to mention Newt Gingrich) occupying the top positions in opinion polls, Gilmore is trying to find a way to break through. As he said yesterday, no one can top his conservative record or match his resume. He was up front about the “cockiness” of such a statement, but that didn’t stop him. Gilmore rattled off several reasons why conservatives ultimately won’t support McCain, Giuliani or Romney.

Today we get a clue as to why Gilmore is taking this approach. According to the Evans-Novak Political Report, Gilmore found himself atop a “push poll” conducted in Iowa. While the poll was designed specifically to boost Gilmore’s standing, Novak sees the results as a clear sign that “The conservative void on the Republican side is simply too great.” Gilmore thinks he’s the man to fill that void.

Can he do it? His first test will come with the CPAC straw poll, the results of which we should know on Saturday night. A good finish — or something respectable — would instantly propel Gilmore from the second tier to a serious challenger.