With an escalating national debate over "Stand Your Ground" laws unfolding across the country, this much is clear: Opponents have so far found little success trying to repeal the laws, and they continue to face a steep uphill climb in their efforts. Here are the four biggest reasons why:

1. GOP-dominated state legislatures. After the first "Stand Your Ground" law passed in Florida in 2005, some version of it spread to more than 30 other states. In most of those states, the GOP controls the legislature, where any changes must be enacted. And even in states that do not lean heavily to the right, repealing the law will be difficult. To wit: New Hampshire, where Democrats control the state House and narrowed their disadvantage in the state Senate in 2012. A recent "Stand Your Ground" repeal effort passed the House there but then was shelved in the Senate.

2. The National Rifle Association. The NRA remains a powerful force in the political and legislative debate. The recent debate over gun laws in Congress is evidence of this. Not only does the group favor "Stand Your Ground," it was heavily responsible (along with the American Legislative Exchange Council) for its passage back in 2005. The NRA came out swinging against Attorney General Eric Holder this week when Holder railed against the law, and it's a safe bet that any threats to "Stand Your Ground" will be met with stiff resistance from the nation's largest guns rights group. "The National Rifle Association will fight any effort to undermine the right to self defense of law-abiding Americans," said spokesman Andrew Arulanandam, when asked about the group's stance. Indeed, the groups that oppose the NRA's agenda -- like Mayors Against Illegal Guns -- may also enter the mix on "Stand Your Ground." But it's not yet clear the extent to which they will wade into the debate. What we do know is "Stand Your Ground" is an NRA-backed law that passed with NRA support.

3. Florida. As both the birthplace of "Stand Your Ground" and the site of the the shooting death of Trayvon Martin -- which catapulted "Stand Your Ground" into the national conversation -- Florida has become a central pivot point in the debate. The Rev. Al Sharpton has called it a "battleground" in the national fight against the laws. But it's unlikely that Florida will repeal the law. The Republican governor has defended it and the GOP controls the sate legislature, which makes it very unlikely state lawmakers will vote to do away with it. If opponents of "Stand Your Ground" were able to repeal or substantially revamp it in Florida, it would lend momentum to the national effort. But that looks like an unlikely proposition at this point.

4. Time. Most state legislatures have concluded their business for the year, meaning that 2014 will be the first opportunity to address the matter in a legislative setting. It is front and center in the news right now, and is the subject of great debate. But will lawmakers and the public be consumed by the matter when legislatures reconvene in a few months? If it does not remain on the radar, it will be harder for opponents to ramp up the repeal effort.