DENVER — After the annual late-summer harvest on his farm in the eastern reaches of Colorado, Greg Brophy has a few friends over, breaks out the handguns and semi-automatic rifles and mows down some rotten watermelons.
The Republican state senator’s melon shoot is a fixture on the political calendar in his rural district near the Nebraska border and a window into the culture of gun ownership in a state that cherishes its frontier heritage.
One of the worst and most high-profile school massacres in American history — the 1999 Columbine shooting that killed 12 students and a teacher — did little to alter that culture. In fact, it is now easier to carry a concealed handgun in the state than it was before Columbine.
Now, six months since a deadly movie theater rampage in suburban Denver, there is a new drive to restrict guns, fueled by the Connecticut school shooting. And Brophy and other gun rights backers worry that the push might bear fruit because of state’s demographic changes.
In recent decades, Democrats have done increasingly well as young coastal transplants flocked to Denver and its suburbs. The traditionally red state helped elect Barack Obama president in 2008 and chose him again in November, when the party won back the legislature.
Those suburban voters are ‘‘further removed from their rural roots,’’ Brophy said. ‘‘I think [Democrats] will overplay their hands and it will cost them, but over the past few election cycles, they’ve been right and I’ve been wrong.’’
Meanwhile, gun control activists worry that the momentum they believe they have after the Newtown, Conn., massacre will fade just as it did after the Columbine killings — without enough of the kind of laws they believe have any chance to reduce gun violence.
In Governor John Hickenlooper’s state of the state speech on Thursday, he called for universal background checks on all gun sales and a broader discussion about firearms regulations. Referencing the Aurora shooting and Columbine, Hickenlooper, a Democrat, said, ‘‘We have shown in Colorado that we can learn from tragedy and make changes.’’
The previous day, Democrats opened the latest legislative session as about 100 worried gun rights activists quietly marched outside to protest the still-unwritten gun control measures.