President Donald Trump still has net negative approval ratings. He still has a super-thin Republican Party majority to work with in Congress. He still has arguably the fiercest opposition from the news media any president has ever faced in U.S. history.

But after the Florida High School shooting left 17 dead last week, Trump has more power than any president before him to take definitive action against gun violence.

That's most likely why a White House official now tells CNBC that the president is "open" to new rules, including banning all guns for certain individuals.

There are several reasons for this, but most of them are very specific to Trump in an "only Nixon could go to China" kind of way.

Trump's constant support for the Second Amendment throughout the 2016 election and beyond won him the strong backing of gun owners nationwide. Overall, exit polls showed 62 percent of gun owners voted for Trump. That's four percentage points better than Mitt Romney did with that demographic in 2012 and a whopping 10 percentage points better than John McCain in 2008.

The National Rifle Association made Trump the biggest beneficiary of its donations and ad dollars. The NRA's political power and financial clout can be debated, but it's fair to say that the pro-gun rights demographic in America trusts Trump.

That trust seems to be holding up. If there was any fear of betrayal, we would have heard it by now in response to his call Tuesday to ban ammunition bump stocks that make semi-automatic weapons act more like machine guns and his repeated call over the last few days to improve background checks for gun buyers:

Of course, neither one of those positions is really in stark opposition to what even the NRA has stated in recent years. But rest assured that there would be gun lobby push back if President Barack Obama or Hillary Clinton had made the same statements.

But Trump can go further than this because he has the unique luxury of being the only real game in town for gun rights activists.

The Democratic Party was not always in lockstep with the most aggressive gun control advocates in this country.

In the 1970s, gun ownership was mostly a bipartisan reality in America. Only a slightly larger percentage of Republicans owned guns than Democrats. Appearing to have at least something in common with gun owners was important for all politicians. We saw that as recently as the 1990s when Bill Clinton made sure to invite the news media along when he went hunting a few times as president and a presidential candidate.

Today, Republicans are now more than twice as likely to own guns than Democrats. Gun ownership and support for gun rights is now almost indistinguishable from party affiliation. More than any Republican president before him, Trump really is the only choice for supporters of this key conservative issue.

Trump is also becoming increasingly interested in "showing up" his predecessors on any given issue.

When it comes to succeeding where others have failed, reducing mass shootings provides this president with a golden opportunity. By contrast, President Obama had stronger poll numbers and a super majority in Congress in his first two years in office and a mandate from his own party. But despite a long list of deadly mass shootings during his presidency, he was unable to introduce or pass meaningful new gun laws during his two terms.

The bar is pretty low for Trump to do better and that has to be almost irresistible for him.

Especially because polls often show that a majority of gun owners are in favor of certain new restrictions on gun ownership. The most recent Quinnipiac poll shows gun owners support stricter gun laws by a 50-44 percent margin.

So with these political winds at his sails, what other new restrictions could Trump propose? Even without congressional approval, he could close any existing loopholes that allow for the relatively few gun sales than can be conducted without such a check. More importantly, he also wouldn't need Congress to order specific federal agencies to redirect current funding to boost school safety.

He would need Congress to go along with other ideas, especially any ban on individuals not previously convicted of violent crimes. Even increasing the age requirement to buy the AR-15 rifle used in the Florida shooting would need Congressional approval. Nothing's guaranteed, but Trump now has more freedom to pressure Republicans to vote for such a measure in the current climate while also forcing Democrats to prove they're serious about passing new laws.

The point is that Trump has very little to lose in this equation. The belief that he will "alienate his base" is a common misconception among those who overestimate the power of the NRA and underestimate the decency of American gun owners.

If Trump wants to get new gun rules enacted, the only person he has to convince is himself.

Commentary by Jake Novak, CNBC.com senior columnist. Follow him on Twitter @jakejakeny.

For more insight from CNBC contributors, follow @CNBCopinion on Twitter.