On the general-election ballot in Illinois, voters will be able to choose from four candidates for U.S. Senate: a Republican, a Democrat, a Green, and a Libertarian.

That might seem like sufficient choice - and it certainly covers a wide political spectrum - but consider that seven candidates were removed by the Illinois State Board of Elections.

That's because Illinois has put so many barriers between people who want to run for office and the ballot. Established parties - Republicans, Democrats, and Greens presently - need to collect 5,000 valid signatures for their statewide slates. Independent statewide candidates and other parties need to collect five times as many valid signatures: 25,000.

Beyond that, the petitions of third parties and independent candidates are often challenged by people working on behalf of Democratic or Republican organizations. This year, Republicans have been most active in the ballot-access wars, perceiving a threat from several limited-government parties.

These challenges have several effects. First, they make the effective signature threshold much higher. "The challenge process effectively turns the 25,000 requirement into a 50,000 requirement to account for potential[ly] invalid signatures," wrote Steve Hellin, the communications director for Illinois' Libertarian Party, in an e-mail.

Second, the financial, human, and time resources required to fight a challenge are significant and come at the expense of traditional campaign activities such as fundraising, advertising, and connecting with voters one-on-one. "Attention is put to the mechanics of existence, which may or may not be especially relevant in actually getting someone elected," wrote Phil Huckelberry, chair of the Illinois Green Party. "It's an absurd approach to democracy."