If you can believe the polls, the vast majority of Americans — and Louisianians — favor criminal background checks before purchases of firearms. That the U.S. Senate cannot pass such legislation says something about the governing process.

After all, the tougher new background check bill — a compromise, with authors from both parties — is the weakest of the proposals advanced after the Newtown shootings in Connecticut, and much less controversial than the idea of resurrecting a ban on so-called “assault weapons,” the federal law in place until 2004.

We commend Sen. Mary Landrieu, D-La., for backing the compromise bill that would have toughened rules on background checks. And we wonder what measure of public opinion Sen. David Vitter. R-La., listens to, as he was among the dissenters blocking the compromise bill.

In 2004, we supported renewal of the assault-weapons ban, as it was supported by law enforcement and President George W. Bush. While we support the Second Amendment and gun ownership, there is no legitimate reason for 30-round clips and military weapons in civilian hands.

However common-sense that law was, the politics were apparently too much in 2004. Now, even its weaker cousin, the background checks bill, gets a majority of senators for it, but the Senate’s rules require 60 votes out of 100 even to take up a bill.

Common sense has taken a back seat to a vociferous and misguided minority who see the Second Amendment to the Constitution as a blank check for gun enthusiasts.