Ron Paul, the libertarian congressman from Texas, announced Monday on a C-SPAN call-in show that he is running for president.
Chuck Hagel, the senator and Iraq war critic from Nebraska, also captured national TV time Monday to announce that he may announce a presidential campaign later this year.
Fred Thompson, the former Tennessee senator who now plays a district attorney on "Law & Order," told Fox News on Sunday he might jump in. (Don't confuse him with the other Thompson, Tommy, former governor of Wisconsin who is already a GOP contender.)
Then there's Newt Gingrich, the former House speaker who recently came clean on the adultery in his past in a presumed attempt to clear the air in advance of a presidential run he may announce in the fall.
All four newbies are Republicans, and all four have made headlines in recent days, inserting themselves into an already turbulent race for the GOP nomination. If all four men run and none of the current Republican contenders drop out, that would bring the party's list to 13 candidates.
Why is this happening?
"It's like in physics: nature abhors a vacuum," says Amy Walter, an analyst at the nonpartisan Cook Political Report. "You have a Republican primary electorate that is not particularly happy with the current crop of candidates, which gives an opening to other folks."
When asked, Republican voters have told pollsters lately that former New York City Mayor Rudolph Giuliani is their top pick for the nomination, but many have also shown a lack of awareness of Mr. Giuliani's issue positions – in particular his support of abortion rights, gay rights, and gun control. Supporters of Sen. John McCain of Arizona, the establishment favorite who led the polls for months, argue that when GOP voters learn the details, they will come home to the man whose positions most nearly match their own, even if he sometimes goes maverick on issues such as campaign finance.
Polls also typically show former Speaker Gingrich running third, even though he has not even launched an exploratory committee, and ahead of former Gov. Mitt Romney of Massachusetts. Governor Romney is raising big money and has hired respected political talent but remains unknown to many voters.
In short, with a presidential race that has started unprecedentedly early, the polls on nomination preferences are not as meaningful as they will be, say, six months from now. Polling right now reflects name recognition and first-blush impressions, analysts say. Giuliani's signature feature is his image of leadership, centered on his performance in the aftermath of 9/11.
But among party activists, there is an unease afoot that the current field of candidates does not contain a trustworthy and true conservative.
Mr. Romney, who some party regulars expect could still catch fire, given his executive experience and wholesome family image, remains questionable to some activists, because of his recent shift to the conservative position on abortion, gay rights, guns, and stem cell research.
"The problem for the Republicans is they have a ton of candidates, and very few really credible ones," says Larry Sabato, a political scientist at the University of Virginia, Charlottesville. "The top three candidates – and I'm not counting Gingrich, despite the polls – all have such serious flaws. That's why over time you'll see each one go up and down and up and down."
That's why a respected former senator like Thompson, who qualifies as a true conservative, may well look in the mirror come fall and say, "Why not me?"
When asked by a TV reporter after his Sunday comment if there really was a place for him in the 2008 race, he replied: "Oh, sure, there's always room for one more."
The question, should he and the others still pondering a campaign decide to run, will depend on whether there's enough money and talent available to mount a credible effort.
For Hagel, who got the entire political world to hold its breath Monday morning for a nonannouncement, the question will also be how much of a constituency is there for a Republican senator who vocally opposes President Bush's handling of the Iraq war. Even though the war is unpopular with the general public, among Republicans, it still has majority support, albeit barely.
For Hagel and all the other possible late entrants, it may be a matter of "getting down in the weeds and hiding until these [declared candidates] start killing each other off," says Ross Baker, a political scientist at Rutgers University, who has served as a fellow in Hagel's office.
Working in favor of Hagel and the others who appear to be long shots is the new primary schedule, which could feature upwards of 20 states holding primaries on Feb. 5, not long after the opening rounds in Iowa, New Hampshire, and South Carolina.
"The idea that somehow, someone will come through with a juggernaut on Feb. 5 and capture all the big-state primaries and march on to victory is questionable," says Mr. Baker.
If the early results are mixed – one winner in Iowa, another in New Hampshire, a third in South Carolina – then the Feb. 5 results might also bring a mix of results, he says, and that might argue for a longer primary season. Whether that opens the door to a late-breaking candidate remains an open question.