Money has always been a part of politics — but it should not be a big, determining factor in the outcome of presidential elections. Throughout my time in public service, I’ve believed truly democratic elections are about ideas, debates and a choice for the future of the country — not about which candidate spends more time fundraising or has wealthier friends.

That is why, in 1974, Congress enacted legislation establishing the presidential public financing system. Passed in the wake of the Watergate scandal, the presidential public financing system has funded primary and general election presidential elections for almost 40 years. The fund has provided opportunities for lesser-known candidates with new and innovative ideas for the direction of America. It supported candidates from Ronald Reagan to Bill Clinton, and has given lesser-known candidates the chance to share their message directly with the American people. The presidential public financing system enriches the political discourse of the country and ensures that the American people have a voice in elections, not just connected insiders, special interests, or wealthy donors.

Unfortunately, the U.S. Supreme Court’s 2010 decision in Citizens United marked a sea change in American electoral politics when it opened the door to millionaires and corporate entities funneling unlimited, secret contributions into our presidential elections. These special interests can now give amounts that dwarf the resources available from public sources, and if history is any guide when large amounts of money are involved, corruption and scandal cannot be far behind.

Coupled with the incredible influx of money from special interests, the public financing system has problems of its own. Current spending limits are too low for the post-Citizens United world, and public funds often come too late in the primary election to really help lesser-known candidates. Presidents George W. Bush and Barack Obama chose in 2004 and 2008 to opt out of the public financing system, and President Obama has called the system “broken.”

Nevertheless, polls show that 70 percent of Americans recognize the importance of the presidential public financing system and want to see it maintained. These Americans understand the corrosive nature of unlimited special-interest money in politics, and they want candidates beholden to the public good, not their corporate sponsors.

That is why I have introduced new legislation to reform and strengthen the presidential public financing system. My bill, the Presidential Funding Act, would eliminate the outmoded candidate spending limits and at the same time greatly increase the role of citizens and small donors in financing presidential elections. The bill would provide public matching funds at a four-to-one ratio for individual contributions of up to $200 each. This would make a $200 contribution by an individual worth $1,000 to the candidate, which encourages and empowers small donors.

At the same time, a presidential candidate using the system would have to agree to a contribution limit of $1,000 per individual as opposed to the current limit of $2,500 per donor. That means ordinary citizens donating up to $200 would have the same impact as any special interest, corporation, or millionaire.

This bipartisan legislation, a version of which was first introduced in the Senate by Senators John McCain and Russell Feingold, is supported in the House of Representatives by Congressmen David Price, Chris Van Hollen and Walter Jones. It greatly increases the role and importance of small donors in our presidential elections and, in turn, dilutes the role and importance of special-interest money. More importantly, by restoring our presidential public financing system, this legislation will allow candidates to spend less time at high-dollar fundraising events and more time making their cases to voters about why they are best-qualified to lead our country.

Although improving the financing of presidential campaigns will not undo the misguided Citizens United decision, it will go a long way toward ensuring that candidates are focused on courting voters and not special interests.

Some say we cannot afford to spend public money on our presidential elections. But the reality is that we cannot afford to let special interests drown out the voices of the regular folks in our presidential elections. Only by saving the public financing system can we protect the integrity of our presidential elections for the future.

Mark Udall, a Democrat, is the senior senator for the state of Colorado.