(CNN) Sen. Kamala Harris on Monday pledged that, if elected President, she would take executive action enacting sweeping gun control measures if Congress fails to send comprehensive legislation to her desk in her first 100 days.

"Enough," says the fact sheet outlining the proposals that the campaign plans to unveil publicly tomorrow. "We're not waiting any longer."

The pledge by Harris to act unilaterally by executive action sharpens her repeated calls on the campaign trail, blasting Congress for failing to act on gun violence, especially mass shootings.

Last weekend at her town hall in Orangeburg, South Carolina, Harris told the crowd, "It is a false choice to suggest you are either in favor of the Second Amendment or you want to take everyone's guns away. We need leaders in Washington, D.C., who have the courage to speak the truth."

The plan, as outlined in her proposal, aims to move closer to federal universal background checks, a first-step move the campaign calls "mandated near-universal background checks." The campaign says this 100-day pledge is just part of the gun safety agenda Harris will pursue as President.

"These are practical solutions and will save lives," said Kris Brown, president of the gun safety group the Brady Campaign. The Brady Bill, passed a quarter decade ago, was a powerful tool requiring federal background checks. But as the Internet came of age, private sellers increasingly turned to the web and were not required to conduct background checks under the law.

Harris' proposal, said Brown, would update the federal law with modern times.

"What people want is for dangerous people to not have easy access to guns," Brown said. "When I look at each of these proposals, that's what she's achieving."

The proposal comes from the decades-long former prosecutor who recently pointed out that she herself is a gun owner.

Harris' pledge lays out four points. The first would mandate what the proposal calls "near-universal background checks by requiring anyone who sells five or more guns per year to run a background check on all gun sales." The target is to classify that seller of more than five guns as a dealer of firearms. A recent CNN investigation highlighted the problem of unlicensed gun dealing in America. An aide said the campaign read the investigation as it was crafting the proposal.

Another part of Harris' proposal would revoke the licenses of gun manufacturers and dealers who break the law and, for the worst cases, the Harris plan would make them criminally liable. It would also fine gun corporations up to $500,000 for each violation, using that money for community-based violence intervention programs and mental health treatment. Currently, a 2005 law called the Protection of Commerce in Arms Act (PLCAA) shields the gun industry from liability when third parties use weapons for criminal purposes, but not from the federal government, argues Harris.

Harris' plan also reverses a Trump administration action that narrowed the definition of "fugitive from justice," which allows a gun sale unless a person can be shown to have fled a state for the purpose of avoiding charges. Anyone with an outstanding arrest warrant would be denied from purchasing a gun under Harris' proposal.

The Harris plan also expands a federal law that prohibits gun sales to domestic violence abusers. Currently, federal law prohibits those sales to a married partner convicted of domestic violence misdemeanors. Harris would apply that law where an abuser is a dating partner.

The Harris campaign makes clear this is an opening salvo in a larger part of her gun safety agenda. Harris has pledged on the campaign trail to enact universal background checks, renew the assault weapons ban and prohibit those convicted of a federal hate crime from purchasing guns.

"The politics on gun safety have absolutely changed," said Peter Ambler, executive director and co-founder of Giffords, the gun safety organization founded by and bearing the name of former Rep. Gabby Giffords, who was shot while in office.

Ambler recalled that John Kerry, the 2004 Democratic presidential nominee, once donned a duck hunting outfit to align himself to gun owners. Today, many of the Democratic candidates routinely talk about fighting the NRA and gun safety measures.

But the shift in Democratic sentiment on gun legislation is likely to haunt at least one contender. Sen. Bernie Sanders in 2005 voted for the Protection of Lawful Commerce in Arms Act, the law that Harris is targeting in her gun policy rollout. During the 2016 presidential race, Hillary Clinton blasted Sanders for the vote that led to the law shielding the gun industry. Sanders pledged at the time he would act to repeal it.

"It has gone from the third rail to a main issue that will provide a key contrast to Donald Trump," Ambler said. "Being first with a proposal like this speaks to Sen. Harris' courage and the degree to which she's speaking to the issue. It's a bold proposal."