WASHINGTON - The uphill drive to pass gun-related legislation in response to the Newtown school shootings takes a key step this week as Democrats bring a package of bills to the Senate while seeking needed but elusive Republican support.
The fate of the package -- which includes universal background checks, a ban on straw purchases and gun trafficking, along with school safety funding -- remains uncertain despite polls showing that most Americans favor the legislation.
Yet Reid and top Democrats including Sen. Charles Schumer of New York are still weighing the best path forward for the legislation. A decision most likely will not be made until after party caucus meetings in the Senate on Tuesday, Democratic aides said.
Reid will need at least seven or eight Republicans to get the 60 votes expected to be needed to overcome a filibuster and pass the legislation.
The most significant complication has been Schumer's inability to reach a compromise with a conservative Republican on what has been called the heart of the legislation: the extension of background checks for buyers in all gun sales, including at gun shows, over the Internet and between individuals.
"Negotiations on this issue are still ongoing, and those negotiations include considering alternative ways for a seller to conduct a background check," other than through a federally licensed firearm dealer, a Democratic aide said Friday.
The gun bill will be at the center of a storm of activity inside and outside the Senate, as gun-control groups try to match and exceed the legendary political muscle of the National Rifle Association and other gun-rights groups.
The NRA spent $16.6 million on television advertising in the 2012 election cycle, including $12 million against President Barack Obama, according to the nonpartisan Center for Responsive Politics, which tracks political money.
"This is the most forward movement we've had in a long time," said Ladd Everitt, a spokesman for the Coalition to Stop Gun Violence, composed of nearly 50 religious, social service and other national groups.
"We just want to generate as much grassroots pressure on senators as we can," he said, noting dozens of events planned in the coming weeks.
Many of them are focused on the same key states where Mayors Against Illegal Guns, co-founded by New York City Mayor Michael Bloomberg, has been running a $12 million ad campaign to pressure wavering Republican and Democratic senators to support the gun package.
Obama will aid the effort by making his second trip in a week to urge Congress to act on the gun legislation when he goes to Connecticut Monday.
The NRA has taken note. It posted a call for action on its website: "Our Second Amendment rights are under siege like never before -- and that means gun owners need to get involved like never before."
The gun legislation faces several obstacles in the Senate.
Sen. Charles Grassley (R-Iowa) is drafting his own legislation, his spokeswoman Beth Levine said, and is expected to try to substitute it for the bill Reid will introduce.
The NRA has circulated amendments to substantially change -- and, gun-control advocates say, weaken -- the bill.
For the anti-trafficking measure, sponsored by Sen. Kirsten Gillibrand (D-N.Y.), the NRA proposes to raise the standard for prosecution to require proof that the straw purchaser buying guns for another person intended the gun to be used in a crime.
The bill now requires showing that the straw purchaser knew or had reason to know the gun would be used in a crime.
Such changes could lure Republicans to vote for the bill.
But Everitt said, "There is a tension right now between getting Republican support and getting good bills approved. We do not want to see this legislation watered down to the point of being useless."