President Trump listening as the attorney general of Indiana, Curtis T. Hill Jr., left, and the attorney general of Florida, Pam Bondi, right, discussed school safety last week at the White House.

WASHINGTON — Here’s how significant things don’t get done in Washington even in a moment of crisis and opportunity.

The president throws out a hodgepodge of ideas but refuses to put his full weight behind any of them. Senate Republicans, grappling for an answer that responds to public clamor but doesn’t alienate their conservative base, focus on a small fix unlikely to satisfy many people even if it could overcome internal divisions. House Republicans say they will wait to see what the Senate does — though history has shown that can be a very long wait. Democrats push for a broad debate that Republicans want nothing to do with.

That’s where Washington stands now on the subject of new gun legislation after the school shooting in Parkland, Fla. Despite immense public pressure in part from students who escaped the shooting, the outlook for any consequential action remains dim as the president and lawmakers diverge on how best to respond. The most widely backed approach would provide new incentives for public agencies to submit information that could disqualify prospective gun buyers to the National Instant Criminal Background Checks System, an action most agree is modest at best.

Even though they support it themselves, leading Democrats consider that proposal, sponsored by Senator John Cornyn of Texas, the No. 2 Republican, to be woefully insufficient given the scope of the mass shootings.

Senator John Cornyn of Texas, the No. 2 Republican, is a sponsor of a proposal that would make significant changes to the National Instant Criminal Background Checks System.

“The Cornyn bill is kind of a fig leaf,” said Senator Claire McCaskill of Missouri, one of the Democrats up for re-election in a state that President Trump carried in 2016.

To Democrats, the fact that the National Rifle Association is not opposed to the proposal is prima facie evidence that it falls short. They are demanding a more robust debate over a series of gun initiatives, notably what they call a “universal” background check system that would cover all gun transactions in…