GOP race one of shooting stars (Bachmann, Perry, Cain), steady constants (Romney, Paul)

One by one, candidates jumped to the front, and one by one, most of the newly minted frontrunners vanished from the lead, often in a tailspin. Since the spring, the shooting star has been a regular feature of the Republican presidential race.

Now that the long runup to the first real voting is nearly over — fewer than 50 days remain until the Iowa caucus — it's easy to look back on the past nine months and find some constants. One fixture, ironically, has been the presence of a comet, bursting brightly and then dimming. There also have been some fixed constellations — Mitt Romney, Ron Paul and Jon Huntsman Jr., each has polled consistently, Romney at or near the top, Paul in the middle and Huntsman at about 1 percent.

As should be expected before the first votes are cast, the eventual Republican nominee remains in doubt. An average of major polls compiled by realclearpolitics.com shows Romney with a .7 percentage-point lead over Herman Cain for the GOP nomination.

However, if we've learned anything, it's that nothing is a given in this race.

No more than four months ago, Michele Bachmann was on the rise coming off a win at the Ames Straw Poll. It was the second-largest turnout in the history of the straw poll, and Bachmann looked like she would be able to take a chunk of the Republican vote as a leading Tea Party candidate.

Enter Rick Perry.

On August 13 Rick Perry caused a media stir and Tea Party rejuvenation as he threw his hat into the ring. Being the social conservative Republicans were looking for, as well as someone experts thought could challenge Romney on economic issues, Perry's numbers skyrocketed. Matthew Dowd, a former strategist for former President George W. Bush, told the New York Times that Perry's campaign would go big or go home.

"He either gets in and gets through the gauntlet of the first month or so and consistently moves forward and wins the nomination, or he's got this terrific flameout," Mr. Dowd said. "There's no middle ground."

Almost prophetic.