Lindsey Graham is 99.9 percent certain he's running for president in 2016. South Carolina's senior senator says he's motivated to run because "the world is falling apart." But it's hard to avoid the conclusion that Graham also wants to pick a fight with Rand Paul on the GOP debate stage, in addition to the many fights this neoconservative hawk would like to pick abroad.

Graham is an able debater and scrappy political survivor. He demolished libertarian-leaning Republican primary challengers seeking his Senate seat last year. So it's not surprising that he thinks he can take Paul down a few pegs. Indeed, he is already working on it. After Paul zinged Jeb Bush on Iraq, Graham took a shot at Paul, suggesting the Kentucky Republican would call a lawyer before striking terrorists.

Yet Graham is, in some respects, a perfect foil for Paul. It's a lot easier for a libertarian-leaning presidential candidate to make a case against aggressive military intervention when the poster boy for the neocon cause is a cartoonish, blustery senator who never met a hyperbole he didn't like. Consider the Palmetto State lawmaker's anti-Paul line: "If I'm president of the United States and you're thinking about joining al Qaeda or ISIL — anybody thinking about that? — I'm not going to call a judge, I'm going to call a drone and we will kill you." A drone strike for your thoughts!

This is part of a larger pattern with Graham — and one that reveals that the neocon position is often little more than tough talk papering over an intellectually hollow core. During a debate over the indefinite detention provision in the National Defense Authorization Act, Graham exclaimed on the Senate floor, "And when they say, 'I want my lawyer,' you tell them, 'Shut up. You don't get a lawyer.'"

The trouble here is that we're not just talking about terrorists, but due process rights for American citizens. Graham finds such constitutional niceties annoying. "Free speech is a great idea," he has said, "but we're in a war."

The South Carolinian also declared he would not "let Congress leave town until we fix this. I would literally use the military to keep them in if I had to. We're not leaving town until we restore these defense cuts."

Graham later insisted he was joking, but Republican presidential candidates don't normally engage in humorous banter about the military coercing a civilian-controlled branch of government into increasing federal spending.

Unlike other hawks in the race, Graham makes it very easy to demonstrate how his outsized foreign policy would lead to big government at home. Graham's contention that the American homeland is a battlefield is ultimately incompatible with constitutionally limited government, something made plain by his frequent willingness to weaken Bill of Rights protections on its behalf.

Also unlike some other Republican hawks, Graham isn't that big of a limited-government guy outside foreign policy. He's defended the Wall Street bailout. He's co-written op-eds with John Kerry demanding cap and trade. He's suggested he's to the left of most Republicans on taxes. Graham has teamed up with John McCain on campaign finance reform and expressed support for a constitutional amendment overturning Citizens United, a fashionable cause on the left.

Maybe the cost of Marco Rubio's "muscular" foreign policy would wipe out the savings from his entitlement reforms. But Rubio is more of a conventional fiscal conservative on domestic policy.

Graham compares unfavorably to Rubio in another way, too. While the Florida senator engages in threat inflation and has a Graham-like slogan about how nothing matters if we are not safe, Rubio also capably wraps his foreign policy in a more optimistic vision of America's role in the world.

In Graham's version, it's almost all fear. When the world is not falling apart, it is "literally about to blow up." Despite Graham's reputation as a Washington grownup on national security, The Federalist's Ben Domenech describes the senator's rhetoric on these issues as "regularly unhinged and bereft of facts."

As Republicans struggle to put Iraq behind them, Graham is doubling down in defense of the unpopular war. While Graham accuses Republicans like Paul of carrying water for Barack Obama's foreign policy, he backed Obama and Hillary Clinton on war in Libya and Syria. Graham's only regret is that we couldn't intervene more.

Finally, Graham is polling near the bottom of the Republican pack. In one recent Fox News poll, he received zero percent — that's zilch, nada — of the GOP vote nationally.

If Rand Paul has to have a hawkish thorn in his side during the primaries, Graham is the one he should want.