President Trump says anyone under 21 should be barred from buying a rifle or handgun and now Republican Gov Rick Scott of Florida has jumped on board in the wake of the latest school massacre. Can it be done?

Legally and constitutionally, the president is on firm ground. A 1968 federal law already bars the sale of handguns to anyone under 21 by licensed dealers. And a conservative-leaning Supreme Court has let the age limit stand unmolested despite appeals by the National Rifle Association to eradicate the law.

What’s more, several Republicans such Sens. Marco Rubio, Pat Roberts of Kansas and Jeff Flake of Arizona have expressed a willingness to raise the federal age limit on all or some rifle purchases — what are legally classified as “long guns.” The semiautomatic AR-15 used in the high-school shooting in Parkland, Fla., that killed 17 people falls into the “long gun” category.

Yet the roadmap on raising the federal age limit for rifle ownership to 21 from 18 is studded with political obstacles, such as a Republican-led Congress and the NRA.

So far most Republicans have been silent on the issue. Most lawmakers are back in their home states with Congress out of session and they won’t return until next week.

The NRA, for its part, quickly rejected a higher age limit despite the president suggesting the influential lobbying group “is ready to do things.”

Longtime NRA leader Wayne LaPierre on Thursday ratcheted up the rhetoric in a fiery speech defending the constitutional right to bear arms and denouncing critics as “socialists” who are using school shootings as a pretext to restrict gun ownership.

Read:Wayne LaPierre: ‘They hate the NRA, the Second Amendment and freedom

Just six years ago, the NRA sought to overturn the handgun age restriction. A federal court ruled against the group, however, and the Supreme Court wouldn’t even hear an appeal.

In recent years the Supreme Court has generally let stand stricter rules passed by the states, such as a law in Maryland banning the sale of military-style rifles like the AR-15 and AK-47.

As a result, the path is wide open for states and the federal government to increase the age limit on the sale and purchase of rifles and shotguns.

(For a summary of gun laws, check the pro-gun-control Giffords Law Center here and the NRA here).

Florida is the first to take a step in that direction after Parkland. Republican Gov. Rick Scott on Friday proposed raising the age limit to buy any firearm to 21. He stopped short of recommending a ban on military-style rifles that Democrats refer to as “assault weapons.”

Don’t expect most states outside of the Northeast to go down that route, however. Republicans control more than half the governorships and statehouses in the U.S. Many in the South and West have actually loosened gun laws in the past decade.

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Even some Democrats are leery. While high-profile Democrats seen as 2020 presidential contenders push for stricter national laws, candidates in House races are tailoring their own strategies to appeal to local voters. The party hopes to win back control of Congress in the fall, but that means it needs wins in some districts where support for gun ownership is strong.

The current political climate in the wake of Parkland, however, raises the odds that state and federal lawmakers might tighten gun ownership laws for the first time in years.

Before he ran for president, Trump had long supported tighter gun laws and his emotionally raw meeting with school-shooting survivors and family victims this week appears to have swayed him.

He surprised many conservatives with his call for a uniform age limit — “[It] should all be 21,” he said — potentially offering political cover to Democrats (and Republicans) worried about political backlash ahead of the midterm elections.