Bloomberg via Getty Images The National Rifle Association can be accused of many things, but not of a weak stance on due process rights.

When the Supreme Court declared for the first time in history that Americans have a constitutional right to keep and bear arms, the late Justice Antonin Scalia made clear that the entitlement "is not unlimited."

Among its limits, he spoke of "longstanding prohibitions on the possession of firearms by felons and the mentally ill," of "laws forbidding the carrying of firearms in sensitive places such as schools and government buildings," and of "laws imposing conditions and qualifications on the commercial sale of arms."

In the wake of a mass shooting at an Orlando gay nightclub on Sunday -- the deadliest in American history -- Democrats seem to be taking Scalia's words and running with them, as they step up their push for a sweeping ban on firearms purchases on anyone belonging to a so-called "terror watch list."

Press reports confirmed on Tuesday that the gunman, Omar Mateen, was not on an FBI watch list at the time he purchased his weapons, even though he had been on it at the time the agency investigated him for potential terrorism ties in 2013 and 2014.

Would keeping Mateen on a government list indefinitely, and then using that information to prevent a gun sale to him, have averted the Orlando massacre?

Democrats far and wide seem to think so -- from President Barack Obama to Hillary Clinton to Democrats in Congress -- and one by one are seizing the moment to legislate away the right to gun ownership by tying it to whoever is on these ever elusive lists.

BRENDAN SMIALOWSKI via Getty Images At a town hall in Indiana this month, President Barack Obama blamed the NRA for blocking efforts to prevent individuals on so-called "no fly lists" from purchasing firearms.

By their own admission, the proposal hasn't been easy to implement. Speaking at a PBS Newshour town hall in Indiana this month, the president lamented that the powerful gun lobby stood in the way of the well-meaning idea of placing Islamic State sympathizers on an anti-gun registry of sorts.

"And we’re allowed to put them on the no-fly list when it comes to airlines, but because of the National Rifle Association, I cannot prohibit those people from buying a gun," he said.

Not to be outdone, the NRA immediately blew Obama's comments out of proportion, with a headline on its lobbying arm's website that's as misleading as it is incredibly apt for what might happen if the president's measure is carried to its logical extreme: "Barack Obama Unilaterally Wants To Strip Your Gun Rights."

But to understand its argument, one must look beyond the Second Amendment the group loves so dear to another part of the Constitution: the one that guarantees due process of law for anyone whose rights the government intends to target.

On this front, the NRA has forcefully and successfully argued government watch lists are constitutionally problematic because they're bloated and sweep far too broadly, ensnaring innocent Americans that otherwise pose no threat to national security -- including one prominent U.S. senator, media pundits, executives, even babies and the late Nelson Mandela.

When anti-gun furor following the Paris terrorist attacks reached fever pitch last year, the NRA pointed to our own coverage here in The Huffington Post to underscore the myriad problems with terror watch lists, and sought to dispel the public misperception that the organization was somehow interested in arming homegrown jihadists.

"The NRA does not want terrorists or dangerous people to have firearms, any suggestion otherwise is offensive and wrong," a statement from NRA spokeswoman Jennifer Baker read at the time.

The NRA's only objective is to ensure that Americans who are wrongly on the list are afforded their constitutional right to due process. National Rifle Association spokeswoman Jennifer Baker

She continued: "The NRA's only objective is to ensure that Americans who are wrongly on the list are afforded their constitutional right to due process. It is appalling that anti-gun politicians are exploiting the Paris terrorist attacks to push their gun-control agenda and distract from President Obama’s failed foreign policy."

Notice the Second Amendment is nowhere in that statement, but due process is. It was the latter constitutional right, which provides citizens a judicial forum to challenge unwarranted government overreach, that brought to the NRA's side an unlikely bedfellow: the American Civil Liberties Union.

The ACLU, which is involved in litigation challenging the constitutionality of no-fly lists -- one of many watch lists the government keeps -- went as far as to get behind Republicans in Congress who defeated a Democratic-backed gun control measure that relied on the furor following December's San Bernardino attacks to get traction.

"We disagree with Speaker Ryan about many things. But he’s right that people in this country have due process rights," wrote Hina Shamsi, the director of the ACLU's National Security Project. "We want to see them respected."

Shamsi, one of the leaders in the ACLU's years-long constitutional challenge to government watch lists, told The Huffington Post that her organization's issue isn't with sensible gun legislation, only with misguided attempts to cast a wide net that might implicate innocent Americans.

"There’s no constitutional bar for the reasonable regulation of guns," she explained, echoing Scalia's guidance. "And government watch lists could theoretically serves as a means to do that, but only with major overhaul of the watch-listing system because it uses vague and overbroad standards, the result of which innocent people are blacklisted without a fair process to correct government error."

The Michigan chapter of the Council on American-Islamic Relations, or CAIR, filed a class action lawsuit of its own earlier this year on behalf of thousands of American Muslims who may find themselves on a government watch list for no other reason than their religion or protected First Amendment conduct.

And like the ACLU and the NRA, the group says it simply wants to provide a check on the amorphous "predictive judgments" the government is making when deciding who should belong on a government watch list and who shouldn't.

“These are Americans. And no American has a greater right than any other American," said Shereef Akeel, one of the lawyers spearheading the CAIR lawsuit, which seeks damages for everyone whom the government branded as a "known or suspected terrorist" without due process.

Akeel added that if the people on the watch lists are truly terrorists, then "get them off the streets," but let everyone else challenge their designation, just as the Constitution intended.

With congressional Democrats ready to put up a new fight over gun control in the wake of the Orlando massacre, time will only tell if they'll heed the advice coming not just from the NRA, but from some of its biggest liberal allies.