State Senate Majority Leader Andrea Stewart-Cousins has joined the chorus asking why the state has taken so long to implement a key part of the 2013 SAFE Act by setting up a database to register ammunition sales.

Gov. Cuomo rammed the law through in the wake of the Sandy Hook mass shooting, and several of its provisions kicked in right away. But not the one that required ammunition sellers to determine a buyer’s eligibility by using an online State Police-operated database.

Well, required as soon as the database got built — which it still isn’t. A spokesman for the State Police told the Times Union recently that the database remains a priority, but the six-year delay suggests otherwise. California got its similar system up and running just 2 ¹/₂ years after voters approved its creation.

Other Team Cuomo officials have cited legal issues for the delay, and technical factors like the fact that rural ammo-only dealers had never faced any reporting requirements at all. (Some shops don’t even have Internet access.)

But it’s also clear that political resistance played a role. The Republicans who until this year controlled the state Senate aimed to undermine the ammo requirement from the start, and even got Cuomo to join in a 2015 memorandum officially suspending it until further notice. That didn’t restrict the State Police effort to build the database — but it sure didn’t signal urgency.

Nor is this the only SAFE Act provision that looks weak in hindsight. That law also required owners of semi-automatic rifles and shotguns (i.e., “assault weapons”) to register them. Estimates of the number of such guns in New York run as high as 1 million, but as of this week only 43,801 are registered.

Our point here isn’t to rain on Cuomo or the SAFE Act, which did after all ban the sale of new assault weapons — a cause we’re pushing nationally. Rather, it’s a reminder that it’s a lot easier to pass a law than it is to make it work.