By Jacob Gershman—Associated Press

In the aftermath of the Newtown massacre, gun-control advocates made the most aggressive push to restrict firearms in years.

Ultimately, that momentum would fade. President Barack Obama’s gun-control effort stalled in Congress. And the majority of gun bills proposed and enacted around the country last year actually made it easier — not harder — to own guns, according to the National Conference of State Legislatures.

In “The Shooting Cycle,” a new paper co-authored with a Yale student, South Texas College of Law professor Josh Blackman attempts to explain why gun-control supporters tend to lose ground in the political skirmishing that follows a mass shooting.

He analyzed data from five major polling firms and found that the percentage of Americans in favor of stricter gun support has fallen to 48% in late 2013 from 64% from 1993.

“In other words, after each spike subsides, support for gun control is even lower than it was before the shooting,” he writes. The temporary gains are “powered” by emotions and by their nature fleeting, as views return to normal or “regress to the mean,” he says.

But why, when the dust settles, do gun-control supporters end up with less support for their proposals than existed prior to the event?

Because all too often, according to Mr. Blackman, gun-control supporters aim too high, which only serves to kindle fears that total disarmament is on its way. Citing UCLA law professor and Second Amendment expert Adam Winkler, Mr. Blackman writes that “the fact that ‘[g]uns are permanent in America’ is ‘perhaps the most important’ fact the “gun ban supporters failed to grasp.’”

Fair enough. But what to make of the failure of more moderate legislative efforts, like the federal Manchin-Toomey bill that Congress shot down last year? After all, Manchin-Toomey chiefly proposed closing a loophole in the requirements for background-checks. It didn’t propose confiscation or, for that matter, requiring gun-owners to register their guns the state.

Writes Mr. Blackman:

When people consider Manchin-Toomey, a universal background check bill that specifically does not provide for registration, they substitute that more difficult-to-assess provision with a simpler one: background checks that lead to registration. Even though they may support background checks in the abstract (as the data supports), they oppose a non-existent bill that does more.

He says “opponents of the law are being ignorant, and substituting a difficult judgment for an easier judgment.” For many people, he says, “it is not worth the time and effort to learn about the specifics of laws.”