“The problem is not the existence of political parties, per se, or that there are two major parties,” Ms. Gehl said. “The real problem is the nature of political competition that the current duopoly has created.”

The monopolistic tactics our political parties employ extend well beyond restricting access to their suppliers. Much as monopolists in the private sector check access to customers and capital, the political parties also limit access to voters and funding. For example, in my own campaign, the Republican Party invited all primary candidates to attend a Reagan Day dinner, but then allowed only the incumbent, Mr. Barrasso, to address the audience. When I complained to the party chairman, I was told there was nothing he could do.

Not only do challengers like me have no access to that $2.5 billion war chest, but prominent Republican donors explicitly told me they couldn’t contribute to my campaign and risk their donation showing up in public records, for fear of retribution by the party.

As Ms. Gehl and Mr. Porter helped me see, the primary system isn’t broken; by restricting access to suppliers, customers and capital, it functions exactly as intended — to protect the monopoly player. The political parties understand that in a political world made up mainly of partisan-drawn districts, where 90 percent of the seats in Congress are not competitive in the general election, controlling the primary process protects incumbents and controls the ultimate outcome.

Monopolies don’t restrict competition with noticeable barriers because that’s how they get caught. Instead, they hide 1,000 bear traps in the grass, rendering a successful challenge too unlikely for competitors to bother. With 96 percent of the film market in the mid-1950s, Kodak used its market power to bundle the cost of developing photos into the price of the film, making it more expensive to process the film of a competitor. In the ’90s, Microsoft didn’t make it impossible to use Netscape Navigator; it just made sure you never saw the browser on your PC by installing only Internet Explorer on Windows machines. The average users, newer to computers, never realized they had a choice.

Ms. Gehl and Mr. Porter argue that these anti-competitive tactics explain the disconnect between our opinion of Congress and our behavior at the polls. We re-elect incumbents not because we approve of them, but because they have no serious competition.

What I learned in grade-school civics is that democracy works when our representatives are accountable to the voters. The insight I gained running for office is that the partisan primary makes them anything but. Political parties have hijacked our elections and our representatives, making representatives accountable not to voters but to the party and its donors. Fortunately, there are three structural solutions that, if voters are prepared to insist on change, will remove the power of those 1,000 hidden bear traps.