Over the past four months, Rasmussen Reports polling has consistently shown Fred Thompson and Rudy Giuliani holding the top two slots in the race for the Republican Presidential Nomination. During that time, the weekly poll results have shown Thompson’s support ranging from a low of 20% to a high of 28%. Giuliani’s range has been similar, from 19% to 27%. Although Thompson and Giuliani are the frontrunners, both men still have plenty of detractors who say they can’t possibly win the nomination.

For the week ending September 23, it’s Thompson 26% and Giuliani 22%.

Occupying a precarious niche somewhere between the frontrunners and the also-rans are John McCain and Mitt Romney. Both men were early favorites of Washington pundits but haven’t done as well among Republican primary voters. During the past four months, McCain’s support has ranged from 11% to 14%. Romney’s range has been from 11% to 15%.

Romney needs to win in Iowa and win big in New Hampshire if he is to remain a viable top-tier candidate. In both states, he began advertising early, spent more money than any other candidate, and set high expectations. However, his lead is down to just three points in the latest Rasmussen Reports poll of New Hampshire primary voters. In addition to doing well in Iowa and New Hampshire, Romney has to hope that those states have as much impact as they did in the pre-internet era. Interestingly, Romney now has essentially the same tactical strategy that Barack Obama is counting on in the Democratic nominating competition.

McCain has an even tougher road ahead of him. It is hard to see him getting the nomination barring significant mistakes by Giuliani, Thompson, and Romney.

Still, as we noted last week, the race for the Republican Presidential Nomination remains very fluid. Thompson is still seen by Republican voters as the most conservative candidate in the field while Giuliani is seen as the most electable.

Rasmussen Reports conducts national telephone surveys on the Presidential race every night and releases updated data from our Presidential Tracking Poll by noon each day, Monday through Friday.

Those results are based upon a four-day rolling average and provide a quick update on the race.

In addition to the daily tracking poll, Rasmussen Reports provides weekly results to provide a longer-term overview of the race. These updates are based upon nightly telephone surveys. Results are reported based upon interviews conducted on the seven days up to and including the night before posting.

For the seven days ending September 23, 2007 show that Fred Thompson earns 26% of the vote while Rudy Giuliani attracts 22%. They are followed by John McCain at 14%, Mitt Romney at 12%, Mike Huckabee at 6%, and four other candidates who split 4% of the vote while 17% are undecided. Those other four candidates, mentioned by name in the polling question, are Sam Brownback, Ron Paul, Duncan Hunter, and Tom Tancredo (review history of weekly results).

The seven day results typically include interviews with more than 1,000 Likely Republican Primary Voters. This includes both Republicans and those independents likely to vote in a Republicans Primary. In some state primaries, independent voters are allowed to participate in party primaries while in others they are excluded. The margin of sampling error for the weekly update is +/- 3 percentage points with a 95% level of confidence.

Updates prior to July 16 were based upon four days of polling conducted the Monday through Thursday preceding release.

Rasmussen Reports continuously updates general election match-ups and other key stats for all Republican and Democratic Presidential candidates.