As he headed into a White House huddle on gun-control with President Donald Trump and a bipartisan group of lawmakers on Wednesday afternoon, U.S. Sen. Pat Toomey provided ample reminder of how maddeningly difficult it is for lawmakers to reach anything approximating a consensus.

Over the course of a roughly 15-minute conversation with home state political reporters, Toomey, R-Pa., repeatedly tried to have his cake and eat it, too.

He made a push, for instance, for expanded background checks on commercial gun purchases, which is at least a baseline for beginning to stop the kind of massacres that tore through Marjory Stoneman Douglas High School in Parkland, Fla., last month.

He made pleasant noises about restricting gun access for the mentally ill. But provided precious little detail about how he'd tackle the "serious mental health problems and serious illness," that he said was behind the uniquely American plague of mass-murder by gun.

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"We have a serious problem that will require some time and many different approaches to really get a handle on it," he said.

Toomey sprained a rhetorical rotator cuff trying to explain why raising the minimum purchase age on long guns and rifles to 21 was an unconstitutional infringement on Second Amendment rights, while laws banning handgun sales to under 21s are not.

"The question of what is the appropriate point, reasonable people can disagree," he said. "I think it's something we can discuss and debate. I know the majority of 18, 19 and 20-year-olds who purchase long guns do so for hunting or target shooting. That's why they have a rifle or a shotgun.

"It's true that handguns are used to commit crimes with vastly greater frequency," Toomey continued. "The way I look at it, is it good policy to deny law-abiding 18-, 19- and 20-year-olds the option to buy a long gun? I remain skeptical. I'm not convinced the benefits outweigh the costs."

What?

The bereaved parents and loved ones of Parkland, where the accused shooter carried out his deadly spree with an AR-15, might disagree that the benefits of restricting ownership far outweigh the costs, however.

Toomey has also tried to have it both ways on banning bump-stocks, the modification device the Las Vegas shooter used to mow down 59 people and injure hundreds more.

In the wake of the Parkland shooting, Toomey said he "gun safety legislation should focus on keeping guns away from those who shouldn't have them, which is why I am skeptical of banning firearms or firearm accessories outright."

(The NRA, for the record, opposes a ban.)

At an appearance at the state Capitol a week or so later, Toomey said he favored regulating bump-stocks since fully automatic weapons have been regulated for decades. Thus, any device that gives another weapon the capacity of an automatic weapon, should be similarly regulated.

So which is it?

It's true that Toomey has been at least one of the saner Republican voices on gun-control, working with U.S. Sen. Joe Manchin, D-W.Va., to expand background checks.

The duo came within six votes of winning Senate passage of an expanded background checks bill in 2013 after the murders at Sandy Hook Elementary School in Newtown, Conn.

And now that the Parkland kids are, well, everywhere, and high school and middle school kids all over the country - including Toomey's own backyard - have found their voices, the Pennsylvania lawmaker is right when he says the national mood has turned.

"What's changed is the horrific accumulation of these massacres -- that's making a difference," Toomey said. "The outcry from high school kids across the country, that's contributed to this discussion as well. Those are having an effect."

Even so, Toomey, like most Republicans (and some Democrats) is only willing to go so far.

Toomey argued Wednesday that there is no constitutional prohibition against civilian ownership of assault-style weapons.

That's far from a settled question.

At least four times in the past decade, appellate courts have ruled that assault weapon bans are constitutional, The Washington Post reported earlier this month.

And even in the case that gun-rights advocates hold up as definitive, District of Columbia v. Heller, the U.S. Supreme Court was silent on assault weapons, though the late Justice Antonin Scalia did observe that right to gun-ownership was "not unlimited."

Toomey told reporters Wednesday that he's hopes to build additional support for his background checks bill.

He also gave a shout-out to legislation sponsored by Sen. Chris Coons, D-Delaware, making it easier for states to prosecute people who lie about their criminal history on a background check application.

"It's hard to know how confident to be," about the prospects of passage, Toomey told reporters.

"I am confident there is legislation that will get 60 votes if it gets to the floor," including the Coons language, Toomey said. A bipartisan background checks bill sponsored by Sen. John Cornyn, R-Texas, would get overwhelming support, but not universal."

Toomey told reporters he's hoping Trump is "open to these suggestions we have. He has indicated he will do something."

Toomey's contradictions - and policy hair-plitting - are stand-ins for the contradictory positions held by other lawmakers. And they're a reminder of how just how heavy a lift it is to get a bill through the Senate, let alone through House, and onto Trump's desk.

The best intentions have been derailed before - and could be again.