On Tuesday we made the case for why Mitt Romney should pick Wisconsin Rep. Paul Ryan as his vice presidential nominee.

Today we argue the opposite case.

* The Ryan budget: Democrats are salivating — not literally but damn close — over the prospect of Romney putting Ryan on the ticket, believing that by doing so Romney could cost Republicans not just the presidency but the House and Senate due to the controversial budget plan that bears the Wisconsin House Member’s name.

Here’s what David Axelrod, a senior adviser to President Obama’s campaign, tweeted out on Ryan and Romney Monday:

Interesting that Boehner weighed in 4 Portman as VP & not his own member, Paul Ryan. Is he feeling the weight of Romney-Ryan budget on GOP?

— David Axelrod (@davidaxelrod) August 6, 2012

At the center of that budget is Ryan’s call to fundamentally overhaul Medicare, a critical piece of the social safety net that has a huge impact in the life of many people older Americans.

Those older voters are also the most reliable group of voters in every election — and a critical constituency for Republicans. In 2008, Arizona Sen. John McCain won voters aged 60+ by just four points, half the margin that George W. Bush enjoyed in 2004 among that same group.

To beat Obama, Romney has to improve on McCain’s margin among older voters, and Democrats believe that will be simply impossible if he has to defend the Ryan budget every day between now and Nov. 6.

While Romney will undoubtedly have to push back against critiques of the Ryan budget, which he has praised publicly in the past, even without Ryan on the ticket, it would be a thousand times more difficult/complicated if the Wisconsin Republican was his ticketmate.

And does Romney want to spend the final two and a half months of the presidential campaign defending a budget plan he had no hand in crafting? He shouldn’t.

* Congress connection = bad: People hate Congress — and Washington more generally. That Romney has never spent any time in either is a major plus for his candidacy.

Ryan, on the other hand, is very much a creature of the nation’s capital. Not only has he served in Congress since 1998 — he’s currently the chairman of the Budget Committee — but he also did stints as an aide to Sens. Bob Kasten (Wisc.) and Sam Brownback (Kans.) in the 1990s.

Ryan’s tenure in Congress and his perceived closeness to the party leadership — all of whom blessed his budget proposals as the official document outlining their vision — mean that putting him on the ticket would make Romney answerable for everything Congressional Republicans have done in the past decade and, in particular, the last few years since they re-took the majority. Does Romney want to voluntarily take on that burden?

* Political acumen?: One of the most curious — and little known — facts about Ryan is that he is not a terribly political creature, preferring to immerse himself in the wonkiness of budgets rather than study the ebbs and flows of the electorate. (In keeping with that policy focus, Ryan lacks any significant political/consulting team around him.)

That may be all well and good for a Member of Congress but a lack of interest/acumen for the political game isn’t a good thing in a vice presidential nominee.

(If you need evidence of the dangers of picking a veep with little natural political instinct and no one in their inner circle with deep experience in national politics, we have two words for you: Sarah Palin.)

Romney badly needs a vice presidential pick who can be a political asset not a neutral force politically or even a political liability. Ryan could be that on the campaign trail but based on what we know now, picking him would be a clear risk for Romney.

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