WASHINGTON -- President Barack Obama is expected to unveil a series of tough new initiatives Wednesday aimed at curbing violence in America, including an assault weapons ban, but his major legislative proposals might face a difficult time in a reluctant Congress.

Many of the more ambitious plans, such as the assault-weapons ban, may not even get to a vote in the Republican-run House of Representatives. Others include limiting the capacity of ammunition clips and requiring background checks for every gun purchase, regardless of where it occurs.

But Obama, aiming to seize the momentum and help heal a nation still reeling from the Dec. 14 elementary school shootings in Connecticut, intends to try.

"He will broadly address the steps forward that he believes we need to take as a nation to try to reduce the scourge of gun violence in this country," White House spokesman Jay Carney said. "He believes we need to act now.”

The president will be joined at the midday White House announcement by Vice President Joe Biden, his point person on the issue, and children who wrote to him after the shooting in Newtown, Conn. Gun control activists and lawmakers also have been invited. His proposals will include executive actions that don’t need congressional approval, as well as legislation.

Congress offered mixed reactions Tuesday.

Rep. Nick Rahall, D-W.Va., is the kind of lawmaker Obama would need to get strict gun-control initiatives enacted. A National Rifle Association member, he voted against the assault-weapons ban in the 1990s, and said, “At this point, no,” when he was asked whether one could pass the House now.

But Rahall, like many like-minded Democrats and Republicans, is willing to listen in the wake of the massacre at Newtown’s Sandy Hook Elementary School, and other incidents.

“The Saturday morning after Sandy Hook we woke up a different nation,” said Rahall, who’s been a member of Congress since the mid-1970s.

The chief roadblock to major gun-control legislation is likely to come from Republicans, who control the House. Party leaders said they were unlikely to act until the Senate approved such a measure.

Though Democrats control 55 of the Senate’s 100 seats, gun control won’t be easy there, either.

“Is it something that can pass the Senate? Maybe. Is it something that can pass the House? I doubt it," said Senate Majority Leader Harry Reid of Nevada, discussing the assault ban last weekend on PBS.

Carney made it clear that Obama “believes and knows that most all gun owners are highly responsible, they buy their guns legally and they use them safely. He also has seen and believes that most gun owners support the idea of common-sense measures to prevent people who shouldn’t have guns from getting them."

Other items that have been under consideration include: improved database tracking for weapons sales; better enforcement of existing laws, including tougher prosecution of people who lie on their background checks; imposing new limits on imported guns; and allowing the sharing of mental health records.

Gun-control advocates have pressed the president to fill a years-long vacancy for a director of the Bureau of Alcohol, Tobacco, Firearms and Explosives while Congress is on recess, since lawmakers have failed to confirm his choice. They also want him to direct the Justice Department to prosecute those who lie on background-check forms, and to lift a gag order that keeps the public from receiving information about gun traffickers.