Anyone who thought a weakened National Rifle Association couldn't hold off expanded gun laws doesn't understand a key point about American politics: It doesn't take a majority, it takes a pressure point — and the NRA's thumb is pushing down on Senate compromise. The group's rhetoric on broader background checks has been constant, if not ascendant, while President Obama appears to be keeping gun control advocates muffled.

In the days after the murder of 26 people at Sandy Hook Elementary School in Newtown, Connecticut, that balance was reversed. The NRA didn't say a word for days, as gun control advocates pushed through now-familiar exploitation critiques to demand action, until NRA Executive Vice President Wayne LaPierre unveiled a plan that's since stalled as heavy lobbying continues. At the town's memorial, an emotional President Obama called for action — nothing specific, but something. Gun victims "deserve a vote," he insisted at the State of the Union.

They'll get one, but probably not on the measures advocates would have wanted or expected. Earlier this week, we reported on collapsing negotiations between Senators Chuck Schumer of New York and Tom Coburn of Oklahoma, who were tasked with developing a compromise on an expansion of background checks for gun purchases. (Current law only mandates an FBI check of people buying guns from gun stores; private sales, including those at gun shows, don't require a check.) This morning, The Hill reported that the push to include a background check deal in the package the Senate is finalizing today has essentially collapsed.

In the absence of a bipartisan deal, Schumer will introduce an updated version of the Fix Guns Checks Act of 2011. It's similar to the legislation Schumer was discussing with Coburn, Kirk [of Illinois] and Manchin [of West Virginia], but without the latest modifications, such as improvements to get state records into the background check database.

The Fix Gun Checks Act would require a background check for virtually every gun sale and require private sellers to verify the person they are selling to is not prohibited from buying a firearm. It includes exemptions for law enforcement and sales to family members.

Kirk and Manchin are not backing the legislation Schumer will offer in the Judiciary Committee Thursday.

Nor is it likely many other senators will either. The Wall Street Journal reported yesterday that Coburn's opposition was "crucial to reeling in the support of other GOP lawmakers."

Why is Coburn (pictured at left after dinner with Obama last night) so reticent about Schumer's proposal? Because the NRA has leveraged enormous pressure on this issue. The primary stumbling block for a deal is whether or not private dealers would have to retain a paper record of any transactions. Doing so is supported by law enforcement officials interested in tracing gun crimes but is opposed by the NRA, which argues that it's expensive and cumbersome — and worries that it could lead to a database of gun owners. A 1993 law prohibits the government from establishing any such database, and "national database" is a frequent talking point of the gun lobby, and has been cited as a frequent concern of Coburn's since Congress returned in February.

Here's LaPierre earlier this week on Fox Business.

After outlining the arguments above, LaPierre concludes:

It is a huge waste of money. It's going to be selectively enforced. It's going to be abused. And the worst thing: You're creating a registry of all of the law-abiding people in the country who own firearms. I know the politicians say, hey, we'll never use that list to confiscate. That's a pretty darn tall order to believe a promise from people in this town right now.

Today on Morning Joe, Senator Coburn — with a lifetime "A" rating from LaPierre's group — explained the rationale behind his obstinacy, including the challenges to a deal posed by "outside groups."

Note how Coburn's arguments mirror LaPierre's — and where he places the blame on no deal being reached. "Let's do the right thing and enhance [background checks]," Coburn says. "I think we can. I think we'll ultimately get there, even though the outside groups aren't comfortable with it yet."

One outside group is certainly pleased with a measure introduced by Coburn's colleague in the Senate, South Carolina's Lindsey Graham. Yesterday, Graham introduced the background check bill the NRA wanted to see — increasing attention paid to mental illness in existing checks, but not expanding them at all. The move puts more pressure on Coburn to fall in line — something the NRA surely recognizes.

While Coburn laments the pressure of outside groups and Graham rides it, groups that oppose the NRA are being hamstrung by the president, according to a report from Politico today.

The White House knew its post-Newtown effort would require bringing key gun-control groups into the fold. So the White House offered a simple arrangement: the groups could have access and involvement, but they'd have to offer silence and support in exchange.

The implied rules, according to conversations with many of those involved: No infighting. No second guessing in the press. Support whatever the president and Vice President Joe Biden propose. And most of all, don't make waves or get ahead of the White House.

"It's not like they're being bullies," one external participant in White House conversations notes. But if we've learned anything over the past 24 hours, it's that public, visible pressure is a key driver of political action — or at least public political discourse. As the NRA launched a robust campaign to defend its position, Politico notes that the White House led advocates of stricter laws in not responding to LaPierre in an effort to "not elevate" him, letting the group often be the loudest voice in the debate by default.

There is still enormous public support to effect new policies to curtail gun violence. And lawmakers are at the very least talking about doing something — the Senate Judiciary Committee today voted in favor of a gun-trafficking bill as it began debate on the contentious assault weapons ban renewal. But Capitol Hill runs on political cover more often than it does political will. The NRA gives Coburn and other Republicans a lot of cover for their decisions. It's not clear that gun control groups are doing the same, despite emotional pleas from the likes of Gabby Giffords. In an arena motivated by shouting, working quietly is not a proven strategy. And practiced shouters like the NRA are showing everyone else how to get things done.