You know what’s fun? (I mean in addition to watching U.S. Ted Cruz, R-Texas, and U.S. Rep. Beto O’Rourke, D-El Paso, trying to make each other’s head explode.) It’s fun to eavesdrop on a senior U.S. senator and a police chief.

So let’s listen in on a recent Twitter back and forth between ex-Austin and current Houston police Chief Art Acevedo and Sen. John Cornyn, R-Texas, as they discussed guns and gun violence. Cornyn got it rolling, apparently seeking a discussion on the topic with O’Rourke, the current challenger to Cruz.

A funny thing happened when Cornyn did that. A cop kind of pulled Cornyn over, rhetorically speaking. Not just any cop, but Acevedo in a reminder that he remains one of the most interesting and politically involved police chiefs around.

It began with Cornyn tweeting a February video of O’Rourke voicing his concerns about the wisdom and necessity about AR-15s as consumer products in America. Cornyn quoted O’Rourke in the CBS News interview as saying: "I just don’t think we should be selling AR-15s in this country."

Here’s the fuller quote from O’Rourke in that interview: "I don’t know that we should raise the age for buying an AR-15. I just don’t think we should be selling AR-15s in this country. That weapon was designed for one purpose and one purpose only, to kill people as effectively and efficiently as possible on the battlefield. It has no place in our streets and our schools and our concerts and movie theaters. We should not be selling that to civilians."

Cornyn follow-tweeted with this thought about why somebody might perceive a need for an AR-15: "For self defense?"

That got Acevedo to thinking. And tweeting. The chief likes to tweet. He’s posted over 22,000 of them and has almost 57,000 followers. The ol’ boy’s got a lot to say and he’s not shy about saying it.

So here’s how the chief intervened on Cornyn’s failed attempt to draw O’Rourke into a gun-control discussion:

"In 32 years policing I’ve yet (to) encounter a case of a community member using an AR-15 for self-defense," Acevedo told Cornyn. "I’m not saying it hasn’t happened, but I’d bet the house they’ve been used many, many times to slaughter innocent Americans as opposed to self-defense."

Cornyn back-tweeted with: "Chief, it isn’t the gun it is the shooter. Let’s focus on mental health, background checks and information sharing that can save lives."

Acevedo: "It’s past time for Congress to authorize and fund the study of the public health epidemic from gun violence. With research & data we can make evidence-based policy decisions instead of extreme decisions on both sides of the aisle based upon expediency. We can do better."

Still more from Acevedo to Cornyn: "Let’s get robust universal background check with real teeth, red flags for mental health; abusers, etc., close the private seller at gun-show loophole & commission a study to determine why we lead the industrialized world in gun deaths. We put man on moon (we) can address violence."

Cornyn suggested, in a positive and helpful vain: "Let’s work together to build consensus."

"Work together" and "build consensus." Anybody remember how that works?

Lots of other folks tweeted in on the Cornyn-Acevedo conversation. Jim Hanson, president of Security Socials Group, a think tank that identifies as "defending the value of American power against the true threats we face," tweeted "Just AR-15s. Or all semi-auto rifles? What about semi-auto handguns? You know .22 caliber guns kill more people than any other."

Said Cornyn: "Slippery slope."

Indeed. Sadly, the whole important discussion seems to be one too slippery for us to make any meaningful progress on. Not to worry, it’ll come up again — at least temporarily — for a few days after the next mass shooting that’s no longer to horrific to contemplate.