The broad package Obama will announce Wednesday is also expected to include more than a dozen steps the president can take on his own through executive action. Those measures will provide a pathway for skirting opposing lawmakers, but they will be limited in scope, and in some cases, focused simply on enforcing existing laws.
Obama is urging a reluctant Congress to ban military-style assault weapons and ammunition magazines holding more than 10 bullets like those used in the Dec. 14 massacre of 20 elementary school children in Newtown, Connecticut. The president will also ask for a requirement for universal background checks on gun buyers.
The general public appears receptive to stronger federal action, with majorities of Americans favouring a nationwide ban on military-style rapid-fire weapons, according to a new Associated Press-GfK poll. A lopsided 84 per cent of adults would like to see the establishment of a federal standard for background checks for people buying guns at gun shows, the poll showed.
But gun control advocates worry that opposition from the powerful National Rifle Association and its allies in Congress will be too great to overcome.
The NRA released an online video Tuesday that called Obama an "elitist hypocrite" for having armed Secret Service agents protect his daughters at school while not committing to installing armed guards in all schools.
White House officials signalled that Obama would seek to rally public support for the measures he puts forward, perhaps holding events around the country or relying on Organizing for America, his still-operational presidential campaign.
For many Americans, gun ownership is a cherished right protected by the Second Amendment of the U.S. Constitution — 51 per cent in the Associated Press-GfK poll said that they believed laws limiting gun ownership infringe on the public's constitutional right to possess and carry firearms.
Others argue that the country's founders in the 18th century could never have envisioned the sort of high-powered assault weapons used in the Newtown attack.
White House officials, seeking to avoid setting the president up for failure, have emphasized that no single measure — even an assault weapons ban — would solve a scourge of gun violence across the country. But without such a ban, or other sweeping Congress-approved measures, it's unclear whether executive actions alone can make any noticeable difference.
"It is a simple fact that there are limits to what can be done within existing law," White House spokesman Jay Carney said Tuesday. "Congress has to act on the kinds of measures we've already mentioned because the power to do that is reserved by Congress."
Obama will announce his proposals in a midday event at the White House, flanked by children who wrote to him about gun violence following the massacre of 20 students and six adults at Sandy Hook Elementary School. Law enforcement officials, mayors from across the country and supportive congressional lawmakers are also expected to attend.
According to a lobbyist briefed Tuesday, Obama will present a three-part plan focused on gun violence, education and mental health.
The president will call for a focus on universal background checks. Some 40 per cent of gun sales take place without background checks, including those by private sellers at gun shows or over the Internet, according to the Brady Campaign to Prevent Gun Violence.
The president will call for banning assault weapons and limiting ammunition magazines to 10 rounds or fewer, and also propose a federal statute to stop "straw man" purchases of guns and crack down on trafficking rings. He'll order federal agencies to conduct more research on gun use and crimes, something Republican congressional majorities have limited through language in budget bills, the lobbyist said.
Obama has pledged urgent action to prevent future mass shootings, and his plan — coming just one month after the Newtown attacks — is swift by Washington standards.
The president's framework is based on recommendations from Vice-President Joe Biden, who led a wide-ranging task force on gun violence. Beyond the gun control measures, Biden also gave Obama suggestions for improving mental health care and addressing violent images in video games, movies and television.
The vice-president's proposals included 19 steps that could be achieved through executive action.
Obama may order the Justice Department to crack down on people who lie on background checks; only a tiny number are now prosecuted. Such a step has support from the National Rifle Association, which has consistently argued that existing laws must be enforced before new ones are considered.
He also could take steps ordering federal agencies to make more data on gun crimes available and conduct more research on the issue, something Republican congressional majorities have limited through language in budget bills. And he may order tougher penalties against gun trafficking and give schools flexibility to use grant money to improve safety.
Gun control proponent Rep. Bobby Scott, a Democrat who met with Biden on Monday, said the president is also likely to take executive action to ensure better state reporting of mental health and other records that go into the federal background check database. But he, too, acknowledged there were clear limits to what Obama can do without Congress' say-so.
States and cities have been moving against gun violence as well.
New York Gov. Andrew Cuomo on Tuesday signed into law the toughest gun control law in the U.S., and the first since the Connecticut school shootings. The law includes a tougher assault-weapons ban and provisions to try to keep guns out of the hands of mentally ill people who make threats.
The NRA criticized the bill in statement. "These gun control schemes have failed in the past and will have no impact on public safety and crime," the group said.
In Washington, it's unclear how much political capital Obama will exert in pressing for congressional action.
The White House and Congress will soon be consumed by three looming fiscal deadlines, each of which is expected to be contentious. And the president has also pledged to tackle comprehensive immigration reform early this year, another effort that will require Republicans' support and one in which Obama may be more likely to get their backing.
Sen. Mitch McConnell, the chamber's top Republican, has warned the White House that it will be at least three months before the Senate considers gun legislation. And Senate Majority Leader Harry Reid, a Democrat, has said immigration, not gun control, is at the top of his priority list after the fiscal fights.
Associated Press writers Julie Pace, Erica Werner, Ken Ritter, Josh Lederman Michael Gormley and Michael Virtanen contributed to this report.