Analysis by Chris Cillizza, CNN Editor-at-large

(CNN) -- Less than two weeks ago, President Donald Trump was mocking Republican Sen. Pat Toomey for being "afraid of the NRA" due to the fact that his bipartisan gun control proposal didn't include a provision to raise the the age to certain types of guns from 18 to 21.

On Sunday night, Trump unveiled his proposal on guns in the wake of the Parkland, Florida, shooting that left 17 people dead. Guess what was left out of that proposal? Yup -- nothing on raising the age limit on the purchase of some types of weapons.

Tweeted Trump of the proposal:

"Very strong improvement and strengthening of background checks will be fully backed by White House. Legislation moving forward. Bump Stocks will soon be out. Highly trained expert teachers will be allowed to conceal carry, subject to State Law. Armed guards OK, deterrent! On 18 to 21 Age Limits, watching court cases and rulings before acting. States are making this decision. Things are moving rapidly on this, but not much political support (to put it mildly)."

So, the reason he didn't push to include raising the age to buy certain kinds of weapons was because he is "watching court cases and rulings before acting"? Or is it, as Trump goes on to note, that there is "not much political support" for raising the age?

On the first reason: There are suits being filed against Dick's and Walmart -- which both raised the age to buy rifles to 21 in the wake of the Parkland murders. And the NRA has sued Florida to block the part of its new law that raises the gun-buying age to 21. The NRA says that violates the 2nd and 14th Amendments.

But those suits are not necessarily a deterrent for the White House throwing its weight behind a proposal to raise the gun-buying age if it so chose. It's a bit of a smokescreen to say that pending legislation ties Trump's hands in any way. If Trump wanted to push on raising the age to buy guns, he could. The litigation is, at best, a secondary concern.

Which brings me to Trump's second point: That raising the age limit lacks public support. This is not, um, true.

In a CNN/SSRS poll conducted late last month, 71% said they supported raising the age limit to 21 to buy any sort of gun -- a proposal that goes beyond even what Trump was advocating for in the open meeting he held with members of Congress on guns earlier this month. That support is strongest among Democrats (86%) but more than six in 10 independents (67%) and Republicans (61%) also favor prohibiting gun sales to anyone under 21.

When Trump says that raising the age limit to buy a gun lacks political support, what he is really saying is that it lacks the NRA's support -- and those within his base who view any sort of infringement on 2nd Amendment rights as beginning down a slippery slope to gun seizure.

As soon as Trump floated raising the gun-buying age, the NRA quickly came out in opposition.

"Legislative proposals that prevent law-abiding adults aged 18-20 years old from acquiring rifles and shotguns effectively prohibits them for purchasing any firearm, thus depriving them of their constitutional right to self-protection," said NRA Public Affairs Director Jennifer Baker.

Then, in late February, Trump had lunch at the White House with several top NRA officials who made a direct pitch to him to leave raising the age limit out of any broader gun control measure in response to Parkland.

And now, this. A proposal that focuses heavily on "hardening" schools and arming teachers. And totally leaves out raising the age limit to buy certain firearms.

That omission is not because of pending lawsuits regarding raising the age limit. And it's definitely not because public support -- including among Republicans! -- isn't there for such a proposal.

It's because the NRA didn't want it in there. And Trump is always putting his base -- of which the NRA and single-issue 2nd Amendment voters are a big part -- first.

"I'm a fan of the NRA," Trump said 11 days ago. "I mean, there's no bigger fan. I'm a big fan of the NRA."

He just proved it.