I think I'm going to defend conservative Republicans against the charge that their opposition to New Start is nothing but raw partisan politics. See for example Adam Serwer's claim that treaty opponents are "manufacturing controversy over Democrats adopting policies Republicans once embraced," which Patrick Appell over at the Dish summarizes as "Anything Obama Supports = Bad." This is generally followed by citing the GOP Secretaries of State who support the treaty, as Max Bergmann does here.
There may indeed be some of that disingenuous opposition going on, but really: do these people ever listen to conservatives? It seems to me that what we're mainly hearing here is the wing of the party that considered Henry Kissinger (and Richard Nixon) near-traitors, that considered Ronald Reagan a sell-out when he shifted from giving speeches about the Evil Empire, and that spent eight years of the George W. Bush administration trashing every treaty from ABM to Geneva, of all things. Is it really a surprise that they aren't convinced by Kissinger, Brent Scowcroft, and George Shultz? Nor is it news that this wing of the GOP has considerable support in the Senate; hasn't that always been the case?
(That's the real lesson of Jonathan Chait's gotcha on Richard Perle: that wing of the GOP didn't roll over for Reagan, either).
Now, it's of course possible that a Republican president would find it somewhat easier going in finding Republican votes, although as I write this it looks as if Barack Obama is going to have the votes, after all.. And it's surely interesting to see the current support level of the Perle-Bolton wing in the Senate. Moreover, I do think it's likely that some Senate Republicans did deliberately draw out the debate in hopes that it would crowd other items off the Senate agenda -- which is, as far as I'm concerned, a perfectly legitimate tactic.
But that's about it. I see no reason to attribute conservative opposition to New START to anything other than conservative opposition to all treaties.