Time for the White House to start lowering public expectations about the big gun-control push, in case something substantial passes Congress and Obama’s inevitably forced to explain in a few months why mass shootings are still happening. They’ve spent six weeks insisting that something must be done to prevent future Newtowns. New talking point: You can’t prevent future Newtowns.

“Nothing we’re going to do is going to fundamentally alter or eliminate the possibility of another mass shooting or guarantee that we will bring gun deaths down to 1,000 a year from what it is now,” Biden told reporters Thursday afternoon after he spent over an hour lunching with Democratic senators at the Capitol.

“But there are things that we can do, demonstrably can do, that have virtually zero impact on your Second Amendment right to own a weapon for both self defense and recreation that can save some lives,” he said…

“I’m not saying there’s an absolute consensus on all these things,” Biden said, “but there is a sea change, a sea change in the attitudes of the American people. I believe the American people will not understand — and I know that everyone in that caucus understands — they won’t understand if we don’t act.

If there really was a sea change, I’m thinking Mark Pryor would feel as safe voting yes on Feinstein’s new assault-weapons ban as he did when he voted yes on the old one nine years ago. As it is, Democrats face a real possibility of getting fewer votes for the new ban than they did in 2004. But give Biden credit for acknowledging reality, even if it’s in service to covering his ass. He likely knows what the weapon of choice is for most mass shooters, and no one’s going to be banning that one:

The basic pattern found by the New Jersey DHS fusion center, and obtained by Public Intelligence (.PDF), is one of a killer who lashes out at his co-workers. Thirteen out of the 29 observed cases “occurred at the workplace and were conducted by either a former employee or relative of an employee,” the November report finds. His “weapon of choice” is a semiautomatic handgun, rather than the rifles that garnered so much attention after Newtown. The infamous Columbine school slaying of 1999 is the only case in which killers worked in teams: they’re almost always solo acts — and one-off affairs. In every single one of them, the killer was male, between the age of 17 and 49.

Calling for a ban on semiautomatics is too risky given how popular that type of weapon is, so “assault weapons” become the default target if you’re inclined to Do Something — even though, by the vice president’s own admission, you’re not doing much. As I noted once before, neither of the semiautomatic pistols that Adam Lanza had on him while he was firing on defenseless children with a rifle are forbidden under Feinstein’s new AWB. If he hadn’t had the rifle, there’s every reason to believe he would have used the handguns to carry out his plan.

In case you missed it elsewhere, here’s new video from DHS with pointers on what to do if ever you find yourself confronted by an armed lunatic on a rampage. Spoiler alert: Hiding and staying quiet are good ideas. Calling the police is good too. And if you’re up for playing the hero, you might try to take the gunman out by reaching for your … scissors. Good luck.