A MONTH after the killings in Newtown, Connecticut, the White House and a loose coalition of activists are hoping to harness the public disgust to force Congress to pass its first significant gun control legislation in almost 20 years.
In Washington, Barack Obama and Vice-President Joe Biden will announce their proposals for action, surrounded by children who wrote to the President after the massacre.
Obama announces sweeping gun control measures
US President Barack Obama announces gun control measures including background checks and a ban on assault weapons.
It is thought they will call for bans on military-style semi-automatic weapons and high-capacity magazines as well as extending background checks for what is known as the secondary market.
Mr Obama will also detail what action he will take by way of executive order.
''The President certainly hopes that out of the tragedy of Newtown we can achieve progress towards reducing gun violence in this country,'' White House spokesman Jay Carney said.
But many groups and sympathetic politicians are not waiting for Washington to act - either because they are also seizing the moment or because the White House is calling in favours.
Senate Majority Leader Harry Reid recently cast doubt on the congressional prospects of the assault weapons ban.
''Let's be realistic. In the Senate, we're going to do what we think can get through the House. And I'm not going to be going through a bunch of these gyrations just to say we've done something because if we're really legislators, the purpose of it is to pass legislation,'' Senator Reid said. ''Is it something that can pass the Senate? Maybe. Is it something that can pass the House? I doubt it.''
Delaware Attorney-General Beau Biden - the eldest son of the Vice-President - said on Monday that his state would act to ban assault rifles, ban gun possession near schools and make background checks mandatory for all schools. He emphasised that as a veteran he had been trained to use assault rifles and knew that they had no place on American streets.
It seems a key part of the control advocates' strategy is to front the campaign with known gun owners to reassure people they are not seeking a blanket ban on ownership.
Soon after the President said he would act, Gabby Giffords, the former Democratic congresswoman who survived being shot in the Tucson mass attack, said she and her husband were establishing a fund-raising committee to support the campaign.
She also emphasised that she was a gun owner who supported the Second Amendment.
Also on Monday, Maryland Governor Martin O'Malley said he would pursue assault-rifle bans and tighten licensing laws, while on Tuesday New York became the first state to institute such a ban since the Newtown killings. Similar bills are to be introduced in New Jersey and are being discussed in Connecticut and Colorado.
Mr Obama's former chief of staff, Chicago mayor Rahm Emanuel, this week told the city's pension fund managers to sell holdings in arms manufacturers and called on other mayors to follow his lead. He also plans to introduce to the city bans that mirror those the President wants nationally.