Welcome to the Paul Ryan vice presidential boomlet.

In the past 48 hours or so, talk of the Wisconsin Republican Congressman as Mitt Romney’s pick for vice president has surged — largely due to a piece written in the Weekly Standard urging the GOP presidential nominee to choose Ryan.

Ryan has been a mainstay on our Veepstakes Line — in which we rank the top contenders to be Romney’s pick — for months, and in our last list he was our #3 choice behind only Ohio Sen. Rob Portman and former Minnesota Gov. Tim Pawlenty .

With so much chatter about Ryan, we thought now was a good time to make our cases for and against him to be Romney’s ticketmate. We tackle the case for Ryan today and the case against him later in the week.

(And make sure to check out our cases for and against Portman and for and against Louisiana Gov. Bobby Jindal for vice president.)

* The ideas guy: Republicans have struggled to beat back the growing perception that they lack new ideas and, as a result, have premised their whole existence on simply opposing whatever President Obama proposes. (The Post’s Ezra Klein made the case in a recent post that there is a major policy gap between President Obama and Romney.)

Picking Ryan would immediately change that perception — or at least start to erode it. Like his proposals or not, it’s clear that in his budget blueprints, Ryan has proposed a conservative full world-view that makes tough choices — re-making Medicare, for one — that offers voters a genuine policy alternative to what President Obama has done over the past four years.

For those in the party — led by Wisconsin governor Scott Walke r — who have been urging Romney to lay out a positive policy vision for the country, picking Ryan would be regarded as a master stroke.

* A little bit country, a little bit rock and roll: In the most simple of terms, you can break down Romney’s choices for VP into two categories. There are the safe but less-than-scintillating picks (Portman, Pawlenty) and there are the rock-star-but-riskier picks (Florida Sen. Marco Rubio, New Jersey Gov. Chris Christie).

Ryan is the closest thing to a hybrid of those two categories. (You can make an argument here for Jindal but we tend to think Ryan trumps him on the “star” front.)

Ryan is someone who is well known and well liked by the party establishment, having served in Congress since 1998 and currently chairing the House Budget Committee.

At the same time, Ryan’s budget proposals over the last two years have turned him into a hero among national conservatives (and a villain among liberals, but more on that in the case against Ryan) and he is widely regarded as one of the major figures in the GOP.

It’s easy to imagine that if Ryan is the pick he could draw big crowds — maybe not Sarah Palin-level crowds but close — in places like Iowa and New Hampshire as people scramble to see the new face of the Republican party.

Picking Ryan would combine the credibility of a serious and tested politician with the excitement that only a genuine political star can generate — and that Romney, not exactly Mr. Personality, may need to win.

* Son of the Midwest: If Romney is going to win the presidency, he is going to need to do it in the upper Midwest/Rust Belt states of Wisconsin, Iowa, Ohio and, maybe, Pennsylvania and Michigan.

While we tend to look askance at the alleged power of a geographic pick — the last VP pick to “deliver” a region of the country was Lyndon Johnson in 1960(!) — nominating Ryan would allow Romney to double-down on the idea that the Republican ticket better understands the lives of average Americans in the Midwest. (Romney, remember, was born and raised in Michigan.)

And, more narrowly, Ryan’s popularity in his congressional district in a swing area of southeastern Wisconsin shouldn’t be overlooked. Remember that George W. Bush lost Wisconsin by just 11,000 votes (out of more than 1.9 million cast) in 2004, meaning that even a slight improvement in, say, Ryan’s district might have put him over the top.

With the November election expected to be very close in Wisconsin, you can make the case that a big margin for Romney in Ryan’s district could make the difference.

* An Obama irritant (with a smile): One of the key characteristics for a vice presidential pick is a willingness to go on the attack against the other party’s presidential nominee and, in an ideal world, finding ways to get under his skin.

Ryan has proven an ability to do just that over the past 18 months or so as he and Obama have clashed over their competing budgets and what they would (or wouldn’t) do. Who could forget their contentious closed door meeting in which Ryan faced down Obama over how the president was describing the GOP budget proposal? Or Obama attacking Ryan’s plan as “nothing but thinly-veiled Social Darwinism”?

It’s clear from their history that Ryan has unique ability to agitate Obama rivaled perhaps only by House Majority Leader Eric Cantor (Va.). And, as importantly, Ryan has, to date, been able to keep a smile plastered on his face even when hammering Obama. People like politicians with a sunny demeanor — even when they are on the attack — and Ryan definitely qualifies.