"Will Iran reach an agreement on it's nuclear program in 2015?"
A "yes" vote will mean that Iran and the P5+1 reach a mutual public accord on the continuation of the Iranian nuclear program before the end of 2015.
I would pose the questions: will sanctions be reapplied before Obama's term ends (not Dec 31, 2016)?
Obama would veto all reapplication of sanctions before the election, except for the most egregious violation of the agreement, and the Democrats would uphold his veto, because reapplying the sanctions would mean a failure of the agreement, which no governing party would like to admit directly before an election. After the election, Obama might reapply the sanctions himself or threaten to reapply them if he finds the Iranians at fault, to make the transition for his successor easier.
How about, will sanctions have to be reapplied in 2016?
Very true guru! If we had more questions closing every month the site would generate much more traffic, and that would add to accuracy and liquidity in all questions. Ideally there should be at least 2 questions a month closing in each of the three categories (US Elections, US Politics, World Politics.) That would give more than one a week and keep things very lively.
Not a bad idea -- I clicked that I liked it -- but we also need markets that close more frequently rather than at the end of 2015.