The battle for the 2016 Republican nomination has begun in earnest with an aggressive attack by Texas Gov. Rick Perry (R) against Sen. Rand PaulRand PaulWe can put America first by preventing public health disasters Conservative activists want action from Trump McConnell: 'Big challenge' to pass ObamaCare repeal in Senate MORE (R-Ky.) Perry's attack against Paul was both highly personal and deeply ideological, implying Paul is so isolationist that he is unfit to command. Paul responded in kind, suggesting that Perry shares responsibility for the Texas border immigration crisis, which is an attack against Perry's governance in Texas, and an implicit reminder that in Perry's 2016 campaign he took stands on immigration that offended the far right.

Perry is on a roll. He enticed President Obama into a mano a mano duel during Obama's last visit to Texas. Obama took the bait. In terms of GOP nomination politics, the best place to be is juxtaposed head to head against Obama. Obama fell for it, Perry pulled it off. If Perry didn't lapse into conspiratorial rhetoric about immigration, which may play with the far right but raises the "oops" factor with all other voters, it would have been even better for Perry.

Now Perry attacks Paul on issues of war and peace that are on the front pages every day. Within the GOP, Perry probably gets the better of it, with many Republicans being conservative on military issues. Across the nation Rand Paul comes out ahead because, regrettably in my view, America has become a tired nation with little will to exert the influence of a global power. The Perry-Paul conflict will pressure other Republicans to choose sides. Former Florida Gov. Jeb Bush (R), New Jersey Gov. Chris Christie (R), and the GOP's 2012 nominee Mitt Romney will all be smoked out by the fire of the Perry-Paul crossfire. Sen. Marco RubioMarco RubioTop Trump officials push border wall as government shutdown looms Rubio defends Trump: 'This whole flip-flop thing is a political thing' Rubio: Shutdown would have 'catastrophic impact' on global affairs MORE (R-Fla.), who leans to the neoconservative side with Perry, will be closely watched. Rubio will have to show more resolve on military issues than he does on immigration, and claiming he can defeat Hillary ClintonHillary Rodham ClintonTrump faults DNC in Russian email hacks Week ahead: US raises pressure on WikiLeaks Poll: 85 percent of Clinton supporters would vote for her again MORE makes Rubio look smaller, not larger.

The great divide on war and peace between Perry and Paul mirrors a large debate nationally. Democrats face similar divisions. Recently several neoconservatives have moved to identify themselves with Hillary Clinton, positioning themselves while unsettling Democratic liberals and no doubt causing consternation within Team Clinton.

These are big issues of great consequence. The Perry attack against Paul will be viewed as one of those moments of choice, an inflection point that triggers and escalates the kind of great debate that is all too rare in American politics these days. Ladies and gentleman, whichever side you are on, the curtain has risen and the big show of 2016 has begun in earnest on some very big matters.

Budowsky was an aide to former Sen. Lloyd Bentsen (D-Texas) and former Rep. Bill Alexander (D-Ark.), who was then chief deputy majority whip of the House. He holds an LL.M. degree in international financial law from the London School of Economics. Contact him at