The American Federation of State, County and Municipal Employees has entered the Republican presidential race, and the public-employee union could be a serious contender.

AFSCME, which has been a key player in the struggle to defend state and local workers against the anti-union juggernaut launched by newly elected Republican governors and legislators, has long been at odds with Newt Gingrich. When the former House Speaker decided that the fundamental challenge facing the American economic system was the persistence of child-labor laws, AFSCME pushed back with a muscular campaign that asked: “Really, Newt?”

Challenging the speaker’s proposal that school janitors be replaced with “poor children,” AFSCME launched a national campaign that got thousands of Americans to sign a statement that said:

The US outlawed child labor because it denied children the chance at a real education and allowed employers to exploit children—and because children were often injured or killed on the job. That’s why labor unions fought to pass laws outlawing child labor and protecting all workers.

And the people you want to fire and replace with kids? A lot of them are parents. That job puts a roof over kids’ heads, food on the table, and provides them with health care and the chance to get an education. That job is the only thing between a kid and poverty. Firing someone’s mom and hiring the kid for less money isn’t exactly the “process of rising.” It is, in fact, the process of falling. It is the process of exploiting and destroying working families.

The fact that you don’t get that makes you not only out of touch, but utterly unqualified to serve in any elected position, let alone President of the United States. Newt, “You’re Fired!”

But it turned out that Gingrich’s anti-labor zealotry did not make him an outlier in the Republican race. If anything, the man with whom the former Speaker is now locked in an intense struggle for the party’s presidential nomination, Mitt Romney, is just as bad. In fact, it was Romney, not Gingrich, who was the first candidate to air advertisements supporting union-bashing “right-to-work (for less)” laws and promising to go after “union stooges” on the National Labor Relations Board.

So, now, AFSCME has waded into the fight, with the purchase of almost $1 million in advertising time on Florida television stations. The advertising will air in the week running up to the January 31 Republican primary—where Romney and Gingrich are in the fight of their lives.

The advertising, which will make AFSCME a major player in the final week before what could be a definitional Republican primary, targets Romney. And appropriately so. While AFSCME’s got a gripe with Gingrich, the union has just as much reason to be angry with Romney. And the AFSCME ad explains why: Romney’s been engaged with corporations that have gotten in big trouble for Medicare fraud, an issue that is of particular importance to a union whose members provide frontline medical care and assistance to the elderly and the poor.

Citing a devastating Boston Globe exposé of Romney’s creepiest business activities, the ad (which features imagery so stark that it raises the question of whether Romney is one of the undead) asks: “What kind of a businessman is Mitt Romney? While Romney was a director of the Damon Corporation, the company was defrauding Medicare of millions.”

The AFSCME ad also links Romney with Florida Governor Rick Scott, an antilabor Republican who stands accused of engaging in similar business practices, and whose approval rating of 38 percent rivals those of fellow GOP zealots Scott Walker in Wisconsin and John Kasich in Ohio. Among Floridians who think the state’s economy has gotten worse over the past year, Scott is blamed for the circumstance by an almost two-to-one margin over Democratic President Barack Obama.

It is no secret that AFSCME favors Obama, the unions endorsed candidate in 2008 and again in 2012.

Nor is it any secret that AFSCME is looking to weaken Romney, who until the last week or so appeared to be the “inevitable” GOP nominee.

But the union has taken the lead in calling out both Gingrich and Romney. And union leaders tell me they are likely to continue to “play” in what is starting to look like a long Republican primary process.

Polling confirms that the overwhelming majority of Americans oppose Republican attacks on unions—especially the attacks on the collective bargaining rights of public employees. But it is not just Democrats and independents driving those numbers, According to a USA Today/Gallup Poll, which produced similar results to other recent surveys on the issue, 41 percent of Republicans opposed attacks on collective bargaining rights.

Forty-one percent!

That’s more support than any Republican got in Iowa, or in New Hampshire.

So AFSCME has a constituency within the GOP: two of every five Republicans are on the side of the union on its most fundamental issue.

This raises a question. Since AFSCME has a clear constituency for its views within the Grand Old Party, since the union is making big ad buys in GOP primary states, and since it is doing so openly (not with front groups like the Koch brothers–funded Americans for Prosperity) and transparently (not using the Super PAC deceptions employed by Romney, Gingrich and the other contenders), maybe this is the alternative that Republicans—who polling suggests are deeply dissatisfied with their options—need at this point.

Maybe its time to pass over Newt, Mitt, Ron, Rick and whatever hangers-on may remain and find the open space at the bottom of the ballot. Maybe it’s time to write in AFSCME.

Yes, yes, we are all aware that election laws are inflexible; just ask Gingrich about the trouble he’s having getting write-in votes counted in Virginia.

And yes, yes, even if the election laws were more flexible, there might still be some grumbling about the little detail that AFSCME is not, officially, a person. Rather, it is a union of 1.4 million persons.

But this technicality ought not be overblown. Romney says that ”corporations are people.” If we take him at his word, then surely unions are people too.

So there can’t be much objection to counting votes for the union that maintains a position on union issues that attracts more support from Republicans than Mitt Romney or Newt Gingrich is getting: AFSCME.