Over the last three weeks, only one Republican presidential candidate made a significant move in Gallup’s polling — and it was the man at the top.  Mitt Romney put a little space between himself and the rest of the pack, adding seven points to get to 24% while the rest of the field only shifted within the margin of error.  But is a eight-point lead enough to anoint Romney an early frontrunner?

Republicans’ support for Mitt Romney as their party’s 2012 presidential nominee has increased significantly to 24%, compared with 17% in late May. As a result, Romney has widened his advantage over Sarah Palin in the latest update on rank-and-file Republicans’ nomination preferences. …

Romney appears to have gotten a boost in recent weeks after the official announcement of his candidacy. Gallup’s prior update of May 20-24 came just after former co-leaders Mike Huckabee and Donald Trump announced they were not candidates for the nomination; that poll showed Romney and Palin in a virtual tie. Since then, Romney’s support has increased and Palin’s has been flat, leaving Romney with an eight-percentage-point advantage.

That is the largest numerical lead Gallup has measured for any candidate since it first began measuring nomination preferences in September. In that initial September poll, Romney held a seven-point advantage over the field of candidates. Romney or Huckabee held slim margins of no more than four points in subsequent polls.

The lead becomes even wider if Palin doesn’t run.  Instead of a 24/16 split with Palin, Romney gets a 17-point advantage over Herman Cain in second place 27/10, followed closely by Ron Paul and Newt Gingrich at 9% each.  Gingrich actually benefits most from a Palin exit, picking up four points over three for Romney and one for Cain, but None/Any/No Opinion picks up three points as well.

In fact, at 18%, None/Any/No Opinion comes in second place in the overall poll, too.  That’s not a base that looks sold on any frontrunner.  As the field narrows, supporters of those candidates who get forced to the margins will accumulate, and Romney may not be the candidate who benefits.  On the other hand, Gallup’s demographic breakdown shows that Romney does have a broad-based reach among primary voters:

• Age: Tied for first with Palin among 18-34YOs, leads in all other categories
• Education: Large lead (35/10) among college graduates, slight edge among all others
• Church attendance: Large lead (25/10) among weekly attendees, significant among monthly attendees (24/17), ties Palin among “seldom/never” attendees 22/22
• Ideology: Significant leads among conservatives (25/15) and others (23/17) over Palin

Even with his statements about anthropogenic global warming and ethanol subsidies, Romney appears to have had a good month, and the rest of the pack seems to have had difficulty gaining any traction.  Gingrich’s plummet to 5% may have helped Romney, at least temporarily.  However, if Rick Perry jumps into the race, expect these numbers to shift almost immediately — especially among conservatives.