Choose a candidate from each modern cycle to go drinking with

[Mr. Smith]

Let's suppose I went full-on Jack Mormon for a night,  or managed to ask the bartender for a glass of milk in place of alcohol, or secretly kept substituting in my own non-alcoholic beverage just to do this.[No, I wouldn't do any of those since I don't care for the noise of bars anyway even without the straight-edge thing, suspend the disbelief for a moment anyway] I think it'd be.

1972: Muskie
1980: Reagan
1984: Reagan
1988: Biden
1992: Clinton
1996: Clinton
2000: Bradley
2004: Clark
2008: Obama*, Romney
2012: Cain*, Romney
2016: Graham

For 1976, the coolest candidate to hang with is/was Mormon anyway (Mo Udall) so no need to even think about that one

For 2008 and 2012, a night with Obama and Cain would be more fun than Romney [he's the one big name politician I have met in person, so I know], but I'd rather not have to go to any bars to either compromise any principles or play elaborate charades if there was an alternative and there was more to talk about from the outset anyway.