WASHINGTON  The Senate on Tuesday refused to take up a bill that would require more disclosure of the role of corporations, unions and other special interests in bankrolling political advertisements, after Democrats failed to persuade even one Republican to support it.

The bill was drafted in response to a Supreme Court decision in January allowing unlimited campaign spending by corporations and interest groups.

President Obama and Democratic leaders have been seeking to use the Republicans’ opposition to the bill to portray them as beholden to corporate interests. Republicans, in turn, say the Democrats drafted the legislation in an effort to gain an advantage in this year’s midterm elections.

But the bottom line was that the court’s decision now stands, helping define the November election and, perhaps, campaigns in years ahead. Democrats pledged to try again in September, but the bill’s chances seemed dim.