Many Americans expected a real change in the nation’s gun laws after the killing of 20 first-graders in Newtown. But three months later, the outcome looks unclear. No fewer than four pieces of legislation have passed a Senate panel over the past two weeks to move to the Senate floor. “It’s a step forward,” Debra DeShong Reed, spokeswoman for the Brady Campaign to Prevent Gun Violence, told msnbc.

At the same time, legislators in both the House and Senate have stuck provisions into spending bills that could undermine federal enforcement of both existing and proposed gun control efforts. “It’s gonna be a slog,” Ladd Everitt, spokesman for the Coalition to Stop Gun Violence, told msnbc.

“The will is there,” Josh Sugarmann, executive director of the Violence Policy Center, told msnbc. Sugarmann is a longtime gun control advocate who grew up in Newtown decades before this past December’s tragedy. “But the NRA is relentless,” he added. “They are out there in public. They are working behind the scenes, and that is what we are seeing right now.”

On Thursday the Senate Judiciary Committee passed the Assault Weapons Ban in a 10-to-8 vote along party lines. But even the bill’s supporters concede that it has little chance of ever passing even just the Senate.

“The road is uphill,” Sen. Dianne Feinstein, who proposed the legislation, told reporters after the committee vote. “I fully understand that.”

The bill would ban all new sales of semi-automatic rifles and pistols that can both accept a detachable magazine and have one other military-style feature like a pistol grip, along with semi-automatic shotguns that either have similar features, or that can hold more than five rounds. The legislation would also limit all high-capacity magazines to no more than 10 rounds.

To gun control advocates, banning assault weapons makes a lot of sense. If the bill were to become law, it would restrict every type of weapon used in America’s two worst gun tragedies over the past eight months.

An AR-15 semi-automatic rifle using magazines holding 30 rounds was used to murder the 20 children along with six adults inside Newtown’s Sandy Hook Elementary School. A similar AR-15 semi-automatic rifle, this one equipped with a 100-round drum magazine, was used in Aurora, Colorado, to kill movie goers until the weapon jammed; then the shooter switched to a Glock .40 caliber pistol with a 22 round magazine. The movie theater shooter first opened fire with a pump action, semi-automatic shotgun, firing six rounds. He killed 12 people and wounded 58 others in the Aurora movie theater.

But opposition to the bill among Senate Republicans is so strong that the GOP may filibuster to prevent it from even reaching a vote.

Earlier this week the Senate committee passed another bill in a vote along the same party lines that would apply universal background checks to private gun sales. That would help curb the flow of handguns reaching inner cities across the nation, in addition to staunching the illegal sales of both handguns and rifles across the border into Mexico, according to the bill’s supporters and its sponsor, Sen. Chuck Schumer.

An ABC News-Washington Post poll released this week shows that 91% of Americans favor universal background checks. But opponents like the ranking Republican on the committee, Chuck Grassley of Iowa, argue that the bill would place an undue burden on private gun sales while still failing to stop criminals from obtaining guns.

Last week the committee passed a gun trafficking bill, this time with Sen. Grassley crossing the aisle to vote with Democrats in favor of the legislation. The bill would outlaw “straw” purchases, made when an individual buys a weapon on behalf of someone like a convicted felon who cannot legally purchase firearms.

For each bill passed by the committee, said Everitt, of the Coalition to Stop Gun Violence, “what we want is a vote on the Senate floor.”

But while these bills move to the full Senate, Republicans on both the Senate and House appropriations committees have written four provisions into emergency spending bills that could help undermine the ability of law enforcement agencies to track illegal gun sales, as reported Wednesday by The New York Times. The four provisions were temporary before, but now they are likely to become permanent if they are passed as part of legislation to keep the federal government running until Sept. 30.

The provisions would restrict the Bureau of Alcohol, Tobacco, Firearms and Explosives (the main federal agency charged with enforcing the nation’s gun laws) from requiring gun dealers to conduct annual inventories that agents could inspect to ensure that weapons have not gone missing. Nor could the ATF refuse to renew a firearms dealer’s license for lack of business or evidence of significant recorded gun sales, a technique used to clamp down on dealers who may be using a license mainly as a cover for unrecorded gun sales.

Another provision stuck into the spending bill would prohibit the ATF from analyzing data about gun sales and violence to “draw broad conclusions about firearms-related crimes.” Yet another provision would permanently expand the definition of “antique” firearms that could allow the importation of older weapons that currently cannot be legally purchased in the nation.

The same provisions have been included in appropriations bills on a temporary basis for nearly a decade. But now Senate Democrats have agreed to make them permanent under pressure from Republicans as Congress works to avoid the so-called sequester or automatic spending cuts that would go into effect at the end of this month.

The Senate Judiciary Committee did pass one bill last week related to gun violence that may well make it into law. The School Safety Enhancements Act would expand Justice Department grants to help local officials better secure schools with resources including tip lines, surveillance equipment and more secure entrances.