Lindsey Graham won’t win the White House.

But he did win a Republican presidential debate Wednesday.

No, not the Republican presidential debate — the main event with 11 “top tier” candidates at the Ronald Reagan Library in Simi Valley, Calif.

Our senior senator didn’t get the chance. He wasn’t invited to that one.

Instead, Graham again was relegated to the “undercard” debate, this time with three others (Bobby Jindal, George Pataki, Rick Santorum) at the bottom of the GOP pack.

That warm-up act, also at the Reagan Library, would have featured a fifth tail-ender trying to become a contender if Rick Perry hadn’t dropped out last week.

And Graham would be moving up in the polls if so many Americans hadn’t dropped the notion of our nation serving as world cop.

Even many of us conservatives, sadder but presumably wiser after frustrating U.S. military missions in Iraq and Afghanistan, have lost our zeal for that costly — both in treasure and lives — duty.

Yet even if you don’t buy Graham’s consistent pitches for more U.S. “boots on the ground” in distant, dangerous realms, you should give him fair credit for daring to swim against the risky tide of American retreat.

He made this gung-ho case Wednesday for regaining the U.S. initiative — and doing so under his leadership — in the ongoing global struggle against Islamic radical terror:

“President Obama is making a mess of the world. What I’m trying to tell you here tonight, that Syria is hell on Earth and it’s not going to get fixed by insulting each other. I’ve been there 35 times to Iraq and Afghanistan. I am ready to be commander in chief on Day One. I’ve been in the military 33 years, 140 days on the ground in Iraq and Afghanistan. I am so ready to get on with winning a war that we can’t afford to lose.”

And: “We’ve had one novice being commander in chief. Let’s don’t replace one novice with another. And if I thought I could win this war without more American ground forces in Iraq and Syria, I would tell you, but we can’t.”

Graham asked CNN moderator Jake Tapper to ask the other candidates “the following question”:

“Would you go from 3,500 to 10,000 American boots on the ground in Iraq to destroy ISIL? Because if you don’t, we’re going to lose. Are you willing to send American combat forces into Syria as part of a regional army? Because if you don’t, we’ll never destroy ISIL in Syria. If you’re not ready to do these things you’re not ready to be commander in chief.”

The other candidates eventually said they were willing to do what was needed.

Well, sort of.

Still, none sounded nearly as ready to rumble as Graham.

Keep in mind that when he said “10,000 boots on the ground,” he meant 10,000 troops, not 5,000 troops wearing two boots each.

Maybe Graham’s right about the disastrous hazards of refusing to fully fight the defining conflict of our times.

Maybe we should recall history’s lessons about the folly of appeasing aggressors.

Then again, Graham’s premise that we can’t “win this war without more American ground forces in Iraq and Syria” raises these other scary questions:

How many more troops must we send to how many far-off places and for how long?

How many of them will be maimed and killed?

What is the right way to sustain Reagan’s wise “peace through strength” credo?

How many voters — in and beyond GOP primaries — will buy a hard sell for endless war?

OK, so few Americans would answer those questions the way Graham does at this point. But after a weak outing in the first undercard debate on Aug. 6 in Cleveland, he was at his quick-witted best Wednesday, earning a clear consensus as the victor.

He also was funny. While stressing that our nation needs more, not fewer, young immigrants to help pay the way for the rising ranks of us old folks, he cited the very senior senator he replaced:

“Strom Thurmond had four kids after age 67. If you’re not willing to do that, we need to come up with a new immigration system.”

A few of Graham’s many other good lines:

“If you want to see manufacturing, come to South Carolina. ... I’m not going to tell you things I can’t do. I’m not going to tell you by shutting the government down we’re going to defund Obamacare as long as he’s president. All that does is hurt us. I am trying to lead this party to winning. ... Whether you’re the wedding cake baker or the gay couple or the Baptist preacher, radical Islam would kill you all if they could. Let’s don’t lose sight of the big picture here.”

Of course, “the big picture” occasionally requires big shifts between debate words and presidential actions.

For instance, as previously pointed out in this space, George W. Bush said during a debate with Al Gore on Oct. 11, 2000: “I don’t think our troops ought to be used for what’s called nation-building.”

So what do you think?

After all, politicians aren’t the only Americans who must come up with answers about the war on terror.

And though you don’t have to agree with Graham, ignoring his warnings about the intensifying Islamic radical menace won’t make it go away.

Frank Wooten is assistant editor of The Post and Courier. His email is