They are competing for a nomination that increasingly seems worth having. In July and August, President Obama's job approval has been dropping like a stone. On July 4, the realclearpolitics.com average of recent polls showed it narrowly positive, 47 to 46 percent. On Tuesday, it was negative, 43 to 51 percent.
Obama's approval hasn't topped 46 percent in a public poll since mid-July. It hasn't topped 50 percent in a public poll since mid-June.
Nevertheless, none of the current candidates outperforms the generic "Republican candidate." The seven weeks ahead provide an opportunity for one or more Republican candidates to improve their standing not only among Republican primary and caucus voters but among the general electorate, as well.
Political reporters always like to anoint one candidate as the front-runner. But there hasn't been a real front-runner in the Republican race so far.
Yes, Mitt Romney led in most polls taken up through early August. But I was right to scoff at the notion early in the year that Romney was a real front-runner and wrong when I relented later and said he had earned that status.
Romney's early lead was largely the product of name identification gained through his unsuccessful run in 2008. Yet if you look at the primary returns and exit polls that year, he lacked any strong core constituency.
He won his highest percentages in high-income suburbs, but not stunningly high percentages. And high-income suburbs are no longer the dominant force in today's expanded Republican electorate.
Romney's weakness became apparent when Rick Perry zoomed ahead in polls in August. Romney's percentage in the realclearpolitics.com average declined from about 25 percent in July and early August to 17 percent today.
Perry's percentage rose from 13 percent in the first week of the month to 20 percent by the last full week and 29 percent now. A two-to-one Romney lead became a three-to-two Perry lead in a few weeks' time.
But how well do voters outside Texas know Rick Perry? They know that he is governor of the second-largest state and that Texas has produced the lion's share of the nation's new jobs in recent years -- the percentage depends on where you put the beginning and end points of the comparison.
They know that he espouses conservative positions with Texas-size confidence and in a Texas accent. That's an advantage in a party in which 37 percent of the primary and caucus votes were cast in the 14 Southern states in 2008.
Must Watch: Senator Explains Why He Changed From Being a Democrat to Being a Republican | Katie Pavlich