Dark money: the quixotic quest to clean up US campaign financing

The supreme court's 2010 Citizens United decision opened the floodgates for special interests to pour money into elections. Could a constitutional amendment be the answer?

It would, activists testify, restore the public's waning trust in vital US institutions, curb the corrupting influence of big money in politics and give America's ailing democracy a much-needed shot in the arm.

It is also, they acknowledge, dead on arrival.