Washington (CNN) - Even though polls indicate it's supported by the vast majority of Americans, the gun-control proposal with arguably the best chance of Senate passage may very well go down to defeat on Wednesday.
The Senate is scheduled to begin voting Wednesday afternoon on a number of proposals to reduce gun violence, including a bipartisan yet controversial agreement on expanding background checks proposed by Sen. Joe Manchin, D-West Virginia, and Sen. Pat Toomey, R-Pennsylvania. Their proposal would extend current background checks for gun buyers to include gun shows and internet sales.
While Democratic leaders expressed optimism they'd get enough votes to pass the Manchin-Toomey amendment, a CNN tally of senators indicates the measure is probably in major trouble of passing, unless several undecided Democrats and Republicans - mostly from conservative states - throw their support behind the amendment.
Just about every national poll conducted since December's horrific shootings by a gunman at a Connecticut elementary school, which left 20 young students and 6 adults dead, has indicated widespread support for increased background checks. That includes a CNN/ORC International survey released last week that indicated 86% of the public supports some form of background checks that are not currently required by law for gun sales. And 86% of Americans questioned in an ABC News/Washington Post poll released Tuesday said they supported background checks for gun sales on the internet and at gun shows.
The two new polls were also in-line with past surveys by indicating no partisan divide on the question, with the vast majority of Democrats, independents, and even Republicans supporting increased background checks. The ABC/Washington Post survey also indicates that 86% of gun owning households support the proposal.
President Barack Obama's been a vocal advocate for passing gun control legislation, and he's touted public opinion as he pushes Congress to act.
"If our democracy's working the way it's supposed to, and 90% agree on something, in the wake of a tragedy, you would think this would not be a heavy lift," Obama said last week.
But the powerful National Rifle Association, the leading advocate on gun rights, fiercely opposes the Manchin-Toomey compromise. And that influential opposition is a counterweight to public opinion.
And the ABC/Washington Post poll also highlights that activism and engagement may be a factor in this political battle. About one in five gun owners questioned in the survey say they have at some point contacted a public official to express their views on gun control. That number drops by half for those in non-gun households. Nineteen percent of gun owners say they've contributed to an organization engaged in the gun control issue, with just 4% of non-gun owners saying the same thing.
Another factor may be public concerns that increased background checks would lead to a federal registry of gun owners and their firearms, which according to the CNN/ORC poll, is opposed by 55% of Americans. And two-thirds of those questioned in survey said that if the government did keep a list of gun owners, it would eventually use that list to take guns away from people who own them.
To allay such concerns, the Manchin-Toomey proposal includes language to bar the creation of such a federal registry. Manchin, Wednesday on the floor of the Senate, said attempts by gun control opponents to portray his bill as a universal background check measure were lies.
CNN Senior Congressional Producer Ted Barrett contributed to this report