Yes, the joke's been done before (especially because of the nine thousand Mario Party games out there), but now it's on a t-shirt. Yet, that's not where Nintendo stops interfering in politics.
Supporters of presidential candidate (and popular Mii), Barack Obama, have made a ton of 1up themed paraphernalia endorsing the candidate. The "O" in "Obama" was replaced with the green power-up, and the slogan reads, "Obama: 1up for America." Check past the break (or just click here) to see the design made by the Leftique.
Now all we need is some game gear for McCain, and Nintendo will have completely taken over this election.
[Via Game Politics]
Source: Mario-Luigi '08 shirt
Source: Obama: 1up for America gear