This past autumn, special interest groups rushed to South Dakota to attack my record and question my values. Many of their advertisements were harshly negative in substance and tone, and they reflected little respect for fact or substance. At times like this, in anger and frustration, candidates may wish that Congress could and would outlaw such advertisements. After a season of swift boats, in South Dakota and elsewhere, that wish is powerful, and it is understandable. It is also misplaced.

Congress should resist the temptation now, as it considers regulation of 527 organizations, to impose restrictions on independent political speech and voter mobilization. And those who, like me, have long supported campaign finance reform should keep a wary eye on how those who do not really share our commitment would exploit it for their own partisan purposes. Campaign finance regulation should not become the new weapon in the ongoing effort to change the rules — many and different rules — to favor and entrench one party’s political interest

As a consistent supporter of campaign finance reform, I was proud to shepherd the Bipartisan Campaign Reform Act of 2002 — the McCain-Feingold bill — to the Senate floor and through Congress. I believed then, and I believe now, that the bill was necessary to take lawmakers out of the business of asking donors for increasingly large soft-money donations. The soft-money chase was inherently corrupting, and it needed to stop, as my good friends Sens. John McCain (R-Ariz.) and Russ Feingold (D-Wis.) rightly pointed out.

Preventing lawmakers from soliciting unlimited donations was the right thing to do. But limiting American citizens in the independent expression of their views is not. Nor is it sound policy to place obstacles in the path of energetic efforts to both inform our citizens about the great issues of the day and encourage their vote and their participation.

There are undoubtedly a number of Members of Congress who, with the best and most honorable of intentions, support this new bill as an effort to close loopholes in the 2002 McCain-Feingold law. They are concerned about the rising cost of campaigns, the commitment of time to fundraising, and the quality, often sadly lacking, in the quality of our political dialogue. And they fear that 527s and other organizations have found a way around the law that will exacerbate all these problems.

But campaign finance reform is an attempt to limit the potential for corruption and the potential for special interest money to dominate the course of policy. This urgent concern, effectively addressed by McCain-Feingold, simply does not justify a legislative attack on independent groups, which represent deeply committed citizens from around the country, that raised and spent money — and, yes, it was a lot of money — to speak out on the issues of war and peace before the American public in the last campaign.

This new legislation does more than just outlaw independent political speech. It also will undermine and limit the kind of get-out-the-vote activities that were so successful in the previous election cycle in boosting electoral turnout to a 25-year high. Much of this increase is due to the efforts of independent groups to register and mobilize Americans around issues and causes independent of the political parties.

Will Congress now punish these groups for their success by curtailing their activities?

We supporters of the 2002 law promised the American people that McCain-Feingold struck a careful balance between ending the chase for soft money and preserving political speech and the right to organize for common political goals. This new effort mistakenly undermines that promise by broadly circumscribing the ways in which American citizens can express and organize themselves for political purposes.

Sadly, I fear that may be the motivation for some supporters of this new 527 legislation. All around us we see signs of a majority determined to change the rules in its favor. Those who are determined to alter the longstanding rules of the Senate to end the rarely used judicial filibuster, or the rules of the House to thwart the ethics process, may now be engaged in a similar effort to suppress political activity at odds with their agenda.

It is simply no accident that this administration and its allies in the Congressional majority, furious over the attacks on its record by ACT, MoveOn.org and other groups, have abandoned their resistance to reform and energetically support this bill. The Republican National Committee has filed suit against these same organizations, seeking to punish them for these same political sins, after having intervened at the Federal Election Commission to stop them altogether. So, as they have in other high-consequence contexts, it seems that those unhappy with expressions of dissent have donned the mantle of “reform” and seized on the tactic of changing the rules to stifle it.

There may be too much money in our politics and, as a result, too little public confidence in our government. McCain and Feingold are right to be concerned about that trend. But attacking 527s in this fashion is not the way to address that concern.

It may be tempting to some to legislate out of existence speech we find objectionable or activities that are at odds with our agenda. But Congress would be wise to resist such a temptation, and Americans everywhere, regardless of party affiliation, should insist that it do so.

Former Senate Minority Leader Tom Daschle (D-S.D.) works in the Washington office of the Atlanta-based law firm Alston & Bird.