Congressional Democrats are renewing their push for gun control measures in the wake of the Orlando terror massacre, arguing the best way to prevent suspected terrorists from carrying out acts of violence is to legally limit their access to firearms.

Republicans have their own proposals for confronting the terror threat, and warn that certain gun control measures could make Americans less safe. House Speaker Paul Ryan on Tuesday touted proposals to improve refugee screening and other measures to deal with homegrown terrorism.  

But while some Democrat-backed gun proposals have little chance of passing -- like a reinstated assault-weapons ban, a move President Obama endorsed Tuesday -- others could gain traction in Congress. 

Sen. Dianne Feinstein, D-Calif., and Sen. Charles Schumer, D-N.Y., specifically are pushing a proposal to the top of the Democratic agenda that would bar suspected terrorists from purchasing guns and explosives. 

The bill would allow federal authorities to block gun sales to anyone on a government watch list or whom federal officials believe might use the gun in a terror attack. 

“If the FBI believes there is a reasonable chance someone is going to use a gun in a terrorist attack, it should be able to make that determination and block the sale,” Schumer said. “If it had that belief about the shooter in Orlando, it should have had the authority to act. But it couldn’t, so we will never know what could have been.” 

It’s unclear whether such measures would have prevented the Orlando massacre. The shooter, according to the FBI, was on a watch-list between May 2013 and March 2014 – but apparently just bought two guns, legally, in the week before the attack. 

Republicans, meanwhile, have warned that one incorrect entry on a watch list could deprive someone of their Second Amendment rights.

But Democrats contend the measure, which was initially proposed by President George W. Bush, would include an appeals process for anyone who thinks they were unfairly put on a watch list or denied a gun. 

The measure is attracting some support outside the Democratic ranks. 

On Tuesday, Maine’s Republican Sen. Susan Collins and independent Sen. Angus King said they’d be ready to support the measure.

“I don’t know why we have a process that would not let people buy a ticket for an airplane, but would allow them to buy a gun,” King told The Press Herald.

Collins, who had voted against a similar measure Feinstein introduced last year because it cited an overly broad “terrorist screening database,” said in a written statement that she would be in favor of using “a much more targeted ‘No Fly List’, with due process protections.”

Feinstein’s December measure came after the San Bernardino shooting and failed mostly along party lines. In that tragedy, California couple Syed Farook and Tashfeen Malik killed 14 people and seriously wounded 22 others.

Schumer claimed if Feinstein’s policy had been in place, it might have prevented Omar Mateen’s bloody weekend rampage at Orlando’s Pulse nightclub where he brutally killed 49 people and injured dozens more in the worst mass shooting in modern American history.

Currently, there is no legal prohibition barring someone on a terror watch list from purchasing a firearm. In September 2014, the FBI told a congressional subcommittee there are about 800,000 names on the official government terror watch database. Names on the list contain both Americans and foreigners who pose a threat to the U.S.

“We are looking for needles in a nationwide haystack,” FBI Director James Comey said Monday. 

There are other Democratic proposals in the works, including their frequently revived call to reinstate the assault-weapons ban. 

“We have to make it harder for people who want to kill Americans to get their hands on weapons of war,” Obama said Tuesday.

But most Republicans say stopping similar tragedies has nothing to do with cutting off access to guns.

"We should not make it harder for law-abiding Americans to defend themselves when radical Islamic terrorists are successfully launching attacks on U.S. soil," Republican National Committee Chairman Reince Priebus said in a statement. 

On Monday, presumptive Republican nominee Donald Trump said fighting off future attacks would involve a temporary ban on Muslim immigration. Trump also called for an expansion to encompass “areas of the world where there’s a proven history of terrorism against" the United States and its allies. 

Trump’s comments drew fresh criticism from House Speaker Paul Ryan, who said a “security test, not a religious test” was needed for immigrants.

"I do not think a Muslim ban is in our country's interest," he said. "I do not think it is reflective of our principles, not just as a party but as a country."

Last week, House Republicans released a 23-page proposal on how to protect the homeland.