How's that, again?

In the State of the Union tonight, President Obama asked Congress

to pass a bill that helps to right this wrong.

referring to the recent Citizens United decision.

Now, this decision was specifically rooted in the First Amendment protection of free speech.

How, exactly is Congress going to pass "a bill" that rights this "wrong." Wouldn't that "bill" specifically have to be a Constitutional amendment that would then be ratified by the states?