By Chris Casteel Washington Bureau ccasteel@oklahoman.comWASHINGTON — Oklahoma Attorney General Scott Pruitt, who frequently has challenged the Obama administration on domestic issues, is now working to thwart one of its goals in the nuclear agreement with Iran. The Republican attorney general and his GOP counterpart in Michigan, Bill Schuette, sent a letter to all 50 governors on Monday urging them to enforce or adopt their own sanctions against Iran. Oklahoma does not have a law regarding the investment of funds with companies that do business with Iran, but more than half of the states have such policies. The Obama administration plans to discourage such state-based sanctions if the nuclear agreement goes into effect. Pruitt spokesman Aaron Cooper said Monday that Pruitt “is hopeful Oklahoma leaders can work together to enact strong sanctions against Iran as soon as possible.” Alex Weintz, spokesman for Gov.Read more on NewsOK.com