Gun-rights advocates have had astonishing success in popularizing permitless gun-carry around the country. But the hurdles to adding new states will soon become much higher.

Louisiana became the latest to join the ranks of states to do away with permitting requirements for concealed carry this week when its legislature officially passed Senate Bill 1. The measure will allow any adult eligible to own a handgun to carry it concealed in public without a permit. Louisiana Governor Jeff Landry (R.) has already pledged to sign the measure into law.

Once he does, the permitless carry count will officially stand at 28 states.

That’s a big win for gun-rights advocates at the end of a long road. But the tally is unlikely to tick up much higher than that, at least not for the foreseeable future.

The momentum permitless carry has enjoyed will soon become a victim of its own success. Over the last 25 years, the policy has spread through Republican-dominated states like wildfire–so much so that there simply aren’t many Republican-controlled states left to go.

Outside Louisiana, there remains just one other trifecta Republican state—South Carolina—that does not already have permitless carry enacted into law. And it, too, could soon join the 28 others this year. Republican lawmakers in the state’s two legislative chambers are currently trying to work out a compromise between the two versions of permitless carry that have already passed the state House and Senate.

Looking elsewhere, North Carolina could offer gun-rights advocates some potential. Republicans currently hold supermajorities in both the state’s House and Senate, which they used last year to override a gubernatorial veto on a repeal of the state’s permit-to-purchase regime for handguns. However, lawmakers have thus far been unwilling to expend similar political capital in pushing through a permitless carry measure.

North Carolina’s Democratic Governor Roy Cooper is term-limited this year, which means Republicans will have a decent shot at retaking trifecta control of the state’s government for the first time since 2016 in the upcoming November elections. A 30th permitless carry state would become much more likely under that scenario, though it is far from certain that Republicans will be able to take back the governor’s mansion.

Beyond that, it isn’t easy to see where else the policy could feasibly go. Assuming the political developments in the Carolinas go gun-rights advocates’ way, that would still leave 20 states with divided or solidly Democratic governments where permitless carry does not stand a chance under present-day political conditions.

That leaves two choices for permitless carry activists looking for opportunities to further the policy’s growth in the near term: litigation or political and cultural persuasion.

In 1903, a legal challenge to a local ordinance in Vermont requiring individuals to obtain permission to carry weapons reached the state’s Supreme Court, which ultimately held that it was “inconsistent with and repugnant to” the state’s constitution. Since then, the state has not required, nor has it even offered, carry permits. For 100 years, it was the only permitless carry state in the nation.

It remains the only one by common law rather than state statute.

Barring a similar judicial reading of a state constitutional arms guarantee, however, it seems far-fetched that modern-day challenges to state permitting laws would result in a similar outcome.

It’s also unlikely that federal litigation will bear much fruit for permitless carry activists. Though it’s an open question whether permitting comports with the text, history, and tradition test articulated by the Supreme Court for Second Amendment cases, key members of the Court notably went out of their way to give their blessing to shall-issue carry permits in the New York State Rifle and Pistol Association v. Bruen decision just two years ago.

That just leaves cultural change as the other alternative. Indeed, the previous trend in gun-carry liberalization, the shall-issue revolution that predominately began with Florida’s adoption of the policy in 1987, could point the way forward.

In that case, clusters of states began adopting shall-issue permitting in sporadic waves over multiple decades before it became the country’s dominant policy. It took hesitant states without a traditional culture of concealed carry time to accept that the practice could be adopted without dramatic public safety consequences. Ultimately, all but six got on board by 2022 before the Supreme Court forced the remaining six holdouts to follow suit in Bruen.

Perhaps if permitless carry can demonstrate lasting success without leading to obvious negative externalities in the states where it’s currently on the books, gun-rights advocates can push for a trajectory similar to shall-issue’s spread in the remaining 20 or so states.

At the same time, the political culture surrounding guns has only become more polarized along party lines since the onset of the shall-issue revolution. There are simply far fewer pro-gun Democrats than there were a generation ago. Gun-control activists have become a much more powerful coalition partner for the party in our current climate. So much so that even long-time shall-issue states under Democratic control are starting to backtrack and increase gun-carry restrictions. That makes the task ahead for gun-rights advocates all the more difficult in blue states, especially as they’ve also become increasingly committed to the Republican party.

Gun-rights advocates have had remarkable success in taking permitless carry from a single-state idiosyncrasy to a mainstream policy over the last generation. But barring a serious cultural shift or unexpected judicial ruling, they may have to settle for success in sixty percent of states. At least, for now.