Under the circumstances, may I suggest another means of encouraging probity in elective office. I refer to term limitations, which can serve ends beyond that of saving congressional souls.
As a consequence, the Court ruled that the limits on campaign spending violated the First Amendment, but it accepted the $1,000 limit on individual contributions on the ground that the need to avoid the appearance of corruption justified this limited constraint on speech.
They may then be willing to cast principled votes based on an educated understanding of the public interest in the face of polls suggesting that the public itself may have quite a different understanding of where its interest lies.
The Court made an exception, however, in the case of candidates contributing to their own campaigns because of the rather reasonable presumption that a candidate is incapable of corrupting himself.
What distinguishes the campaign finance issue from just about every other one being debated these days is that the two sides do not divide along conventional liberal/ conservative lines.