They laughed at us. They mocked our obsession with deficits, pay-fors, appropriations, mandatories, discretionaries, trust funds, scoring, and reconciliation. And now Paul Ryan — budget chairman and fiscal analyst par excellence — is the Republican nominee for vice president of the United States.

It’s a fabulous choice, and not just because it’s a victory for budget nerds.

Of course, Paul Ryan is a superb policy analyst. Ask any CBO director who has been grilled about the intricate details of a budget projection (in my case, Social Security reform). Ryan has a comprehensive grasp of federal budgeting; health, tax, and economic policy; and the relationships among them. For anyone who craves a substance-filled campaign debate over the future of federal policy, there cannot be a better choice.

Yet as good a policy analyst as Paul Ryan is, he’s an even better legislator. Much has been made of the “Paul Ryan Budget.” It’s an inspiring and comprehensive vision for the nation. But Ryan’s personal vision wasn’t immediately embraced by his party. Instead, Ryan had to educate, modify, broker compromise, and cajole — he had to do the hard work needed to get that budget to pass. This nation needs leaders willing and capable of getting the job done.

But foremost Paul Ryan is a great politician. In the glare of attention that surrounds his brains and budgets, this is often overlooked. He’s a seven-term representative who has been elected and re-elected in a district that leans left of center. He survived a concerted assault by the Democrats in the aftermath of the passage of his trademark budget. In an era that seemingly rewards shallow oratorical excellence over substance (see Obama, Barack Hussein), his political brilliance is the capacity to educate on a vision, run on a record of accomplishment, and — yes — stand on his feet and talk persuasively about both.

History has a habit of creating great leaders who rise to meet national crises. The U.S. is in crisis and needs strong leadership. Ryan can provide it. Obama will at best be an eloquent curator of U.S. decline; at worst a willing co-conspirator of catastrophe.

So for good and serious reasons, Paul Ryan is the man. But I would be remiss if I did not mention that Ryan is a great guy. And I jealously and grudgingly admit he brings some serious chick appeal. He’s the leading edge of a generation of young Republicans — Nikki Haley, Marco Rubio, Chris Christie, Rob Portman, Tim Pawlenty, Bobby Jindal, Scott Walker, the list goes on — that will change the public perception of the Republican Party.

The Ryan choice also says a lot about Mitt Romney. To date, the presidential race has been a shallow slapfest devoid of real issues, in which the Romney campaign has appeared to be one-dimensional and slow to counter attack. The Ryan choice suggests that Romney understands what’s at stake for the nation. It shows that he’s secure enough to embrace the ideas of another (a very Reaganesque quality) and marry them to his track record of organizational skill and tactical achievement. And it indicates that he’s prepared for a fight.

Good. It’s going to be a doozie.

The president has been happy to make character assassination the central plank of his re-election platform. He has distorted the Romney record and once abused his office by summoning Representative Ryan to receive a public tongue-lashing. Mitt Romney and Paul Ryan have now laid down the gauntlet: “Mr. President, we stand at a crossroads in this nation’s history. Please rise above name-calling and sloganeering. Let’s have a serious debate about our serious problems.”

That’s what budget nerds do. They make sure the facts add up. They debate alternatives, but ultimately must make a choice. They are impatient with temporizing, delay, and distortion. The revenge of the budget nerds is that our national debate must now be a budget debate.

Paul Ryan is a brilliant choice for that debate.

Douglas Holtz-Eakin is the president of the American Action Forum. He was the director of economic policy for John McCain’s 2008 presidential campaign. He was the director of the Congressional Budget Office from February 2003 to December 2005.