President Barack Obama was in no mood to merely play "mourner-in-chief" on Thursday, after the massacre at Umpqua Community College in Roseburg, Oregon. In his 15th public statement as president after a mass shooting, Obama rebuffed the conservative critics who would soon be accusing him of "politicizing" another tragedy by tying it to gun control. “This is something we should politicize,” the president said, his voice edgy with unconcealed frustration and anger. "This is a political choice that we make to allow this to happen every few months in America."

The state of Oregon, as it happens, is one of the few that have already heeded Obama's call to make gun control a political issue. In May, thanks to the efforts of gun-control advocates who turned the 2014 midterms into a referendum on gun violence, Oregon became the eighth state in the country to pass a near-universal background check requirement for private gun sales. But while that made the state a rare political success story for gun-control advocates, it's also been a lesson in the severe limits of what incremental, state-level reform can achieve without federal action. 

In the national wave of support for gun restrictions that followed the Sandy Hook Elementary School shootings in Newtown, Connecticut, during the 2012 holiday season, Oregon was one of several states that tried to move forward on gun control while Congress remained hopelessly deadlocked. Universal background checks had become the rallying cry of the gun-control movement, and bills passed in Connecticut, New York, Delaware, and Colorado in the months after Newtown. In Oregon, however, a background-check bill stalled for two years, before finally passing in May 2015. What changed? Voters made the kind of choice that Obama recommended yesterday, and booted out the Republican legislators who were blocking it.

The bill had been bottled up since 2013 because the entire Republican caucus in the Senate opposed the overhaul, joined by one Democratic swing vote. In an effort to break the deadlock, national gun-control advocates seized upon Oregon’s 2014 mid-term elections as an opportunity. “It was a situation where you saw there was a political pathway in the legislature,” says Mark Prentice, a spokesman for Americans for Responsible Solutions, the advocacy group founded by former Representative Gabby Giffords.

Taking a page from the NRA playbook, gun-control groups poured money into the selected legislative races, and the governor's race, to carve out that path to victory. Michael Bloomberg’s group, Everytown for Gun Safety, alone spent $600,000 on campaign donations, advertising, and grassroots organizing to help defeat legislators who opposed the background-check bill; the Oregonian cited Everytown as having helped to turn the tide. Two targeted state senators lost—just enough to give Democrats a sufficient Senate majority to push through the background-check bill this past spring. It was the first major gun-control law to pass in Oregon since 2000, and activists were understandably jubilant. “Today is a day to celebrate,” said Anneliese Davis, an activist from Moms Demand Action, an advocacy group affiliated with Everytown. 

Gun-control advocates had won by successfully turning Oregon's 2014 elections into a political referendum on gun control—precisely what Obama is urging the rest of the country to do. “When you decide to vote for somebody, are making a determination as to whether this cause of continuing death for innocent people should be a relevant factor in your decision,” he said on Thursday. “If you think this is a problem, you then should expect your elected officials to reflect your views.”

The political breakthrough in Oregon was encouragng, to be sure: a glimmer of hope that gun control can work as a political issue. But the scope of what Oregon achieved, even after a pitched and expensive three-year battle, was limited. No one could have reasonably expected the new law to stop Chris Harper Mercer from his violent mission on Thursday, especially so soon after it was enacted, even though there is mounting evidence that background check laws do significantly help to reduce homicides. But these laws can only do so much, and Oregon's gun laws remain lax in many other respects. “They don’t have particularly high standards for gun ownership," says Daniel Webster, director of the Johns Hopkins Center for Gun Policy and Research. "They don’t have many types of regulation of gun sellers. They don’t have a permitting process for purchasers." The state also allows concealed-carry on college campuses, and doesn’t regulate large-capacity ammunition magazines. “Last year, we graded Oregon as a D+, and the background check law probably raises that grade to about a C,” says Lindsay Nichols, a senior attorney at the Law Center to Prevent Gun Violence. For those who want to seriously regulate guns in Oregon, there are years of heavy lifting ahead. 

Even if Oregon's gun-control activists could muster the political will to regulate gun ownership far more thoroughly, the state would run up against a hard reality: The most robust state regulations are no substitute for federal action. The absence of federal regulation has created a spotty patchwork of state laws, for instance, making it easy for traffickers to move weapons from places with lax regulations to those with stricter ones.

The story of Oregon's gun-control politics in recent years illustrates the greatest problem gun-control advocates face going forward. The opposition has been practicing ruthlessly effective politics for many decades, and they have constrained the ambitions of gun-control advocates, who have largely focused their attention on politically palatable laws, like background checks. But these laws seek to exclude only narrow classes of people from getting guns; they don't strike at the heart of the problem by reducing the sheer number of guns available to begin with.

Until the political landscape changes dramatically, in ways that are hard to foresee even as the country reels from the last example of what loosely regulated guns can lead to, the changes that pass will be necessarily incremental. That creates yet another political obstacle: Pro-gun advocates can use incidents like Thursday's to dismiss the efficacy of gun control in the first place, and make it harder to build momentum for more ambitious measures. 

The political obstacles have never faded away in Oregon, even in Roseburg itself. Douglas County Sheriff James Hanlin, one of the chief law-enforcement officials responding to Thursday's shooting, has been emblematic of the resistance: He's long been a prominent voice speaking out against the background-check law, and this year joined other Oregon sheriffs in refusing to enforce it. In April 2013, when Vice President Joe Biden was pressing for federal action after the Newtown shootings, Hanlin wrote a letter to Biden, vowing that he would refuse to enforce “unconstitutional” federal gun regulations. “Gun control is NOT the answer to preventing heinous crimes like school shootings,” Hanlin wrote. The sheriff has yet to address the issue again since Thursday's tragedy. But both sides will be waiting to see how his remarks will shape the only path to gun control—the long, hard, political one.