This week’s Rasmussen Reports poll of 587 likely GOP voters finds the Fred Thompson freight train continuing to bear down on Rudy Giuliani. A week ago Thompson had a one point lead, 28%-27%. Two weeks ago, Thompson and Giuliani were tied at 24%, but this week Thompson leads Giuliani 27%-23%. Among voters who identified themselves as conservatives, Thompson leads Rudy by 13 points. However, the former NYC mayor still beats the former Tennessee senator among moderates. The Thompson Effect is even starting to eat away at Rudy’s favorability rating. Giuliani still has a favorability rating among Republicans of 74%, but this is an eight point decline for him since late May.

On the other side of the coin, Thompson’s favorability ratings are continuing to go up. His favorability rating has gone up 7 points to 66%. The other two main contenders for the GOP nomination, Mitt Romney and John McCain continue to hold steady in third and fourth place respectively. Romney gets 12% support in the poll, and McCain 11%. Romney is viewed favorably by 55% of those surveyed, and McCain is once again one point behind him at 55%. McCain also registered a really high unfavorable rating of 40%. This is likely because of his continued support of the wildly unpopular immigration reform bill.

Among the second tier candidates Mike Huckabee is at 3%, and Ron Paul, Congressman Tom Tancredo, Tommy Thompson, Congressman Duncan Hunter, and Jim Gilmore all split 7% of the support. Seventeen percent of those who were asked were not sure who they will support. It is starting to look like Thompson’s entry into this race will have the effect of thinning this field. Giuliani, Thompson, and Romney are probably in this race for the long haul. If McCain keeps sliding, and not raising enough money, I don’t see how he will be able to stick around. Even if Romney stays in the race through the primaries, Thompson’s candidacy, in effect, makes this a two person race for the Republican nomination.

The Giuliani campaign is still trying to act the part of the frontrunner, while pretending that they don’t see the looming shadow of Fred Thompson. The reality though is that the Giuliani campaign is already trying to negate Thompson by shifting their candidate to the right, and talking about 9/11 and terrorism at every opportunity. However, just by looking at their records, it is clear that Fred Thompson is much more conservative than Rudy Giuliani. When Thompson enters the race, he is going to play up these differences and appeal to Southern Christian voters in a way that Rudy can’t. Rudy’s strength will be in the blue states, and he could win enough delegates to make this contest for the Republican nomination go down to the wire, but Fred Thompson will be a giant barrier for him to overcome.

Full Rasmussen Reports GOP poll results 

Jason Easley is the editor of the politics zone at 411mania.com.  His news column The Political Universe appears on Tuesdays and Fridays at

www.411mania.com/politics

Jason can also be heard every Sunday at 6:30 pm (ET) as the host of The Political Universe Radio Show at http://www.blogtalkradio.com/thepoliticaluniverse