Every day, we hear plenty of opinions. Top Democrats and Republicans stay "on message," and usually the nation's major news outlets are in sync. The media landscape remains largely uncluttered, so most people won't get distracted by other perspectives and choices.

The symmetry is dependable and perhaps reassuring. So, at the convention in Philadelphia, the TV networks aired interviews with Democrats who critiqued the speeches by Republicans. Later, in Los Angeles, the TV networks aired interviews with Republicans who critiqued the speeches by Democrats. What variety!

These days, politicians and pundits are working hard to explain how Al Gore and George W. Bush differ. Meanwhile, journalists are apt to bypass the many points of unity. In the media zone, if the major-party candidates agree, the matter is pretty much settled.

When Bush and Gore debate in October, they won't be arguing about their areas of agreement, that's for sure. The duo won't question the merits of NAFTA, the GATT treaty or the World Trade Organization. They won't argue over the global loan-shark activities of the World Bank and the International Monetary Fund; they won't mention the devastating results for the world's poor.

Nor will Bush or Gore challenge the massive power of multinational corporations, at home and abroad. As for the huge U.S. military budget -- the disputes between the candidates will center on how many more billions to lavish on the Pentagon.

As usual, some would-be interlopers are standing in the wings. This year, the main one is the Green Party presidential candidate, Ralph Nader. Despite scant media coverage, his campaign has gained appreciable grass-roots momentum, and polls show him to be the strongest third-party candidate.

But the Commission on Presidential Debates -- set up 13 years ago by the two major parties and amply funded by large corporations -- knows what's best for its backers. The commission is insisting on a strict 15-percent-in-the-polls threshold for participation, a requirement that seems sure to limit the debates to Bush and Gore.

Despite its civic-minded pose, the commission has always been looking out for the interests of the Democratic and Republican parties. It arrived on the political scene in 1987 to hijack the nation's presidential debates -- while ousting the nonpartisan League of Women Voters, a group viewed by the major parties' hierarchies as insufficiently subservient to their desires. At the outset, a New York Times headline got it right: "Democrats and Republicans Form Panel to Hold Presidential Debates."

Back in 1992, there was a breach in the two-party exclusivity. For several months, big media were taken with Ross Perot, who rode high poll numbers into the debates that fall. If there's going to be a populist leader embraced for a time by mass media, why not a pro-corporate billionaire?

Democracy, we're sometimes informed, is a messy business. But let's not make it too messy. The two-party system streamlines the process.

Democracy -- what a concept. No need to let it get out of hand.

The two-party system owes much of its strength to the limitations of news media, which we depend on for information and analysis. Yet the American press has always included some journalists willing to write about the big holes in emperors' new clothes.

In 1941, one of the country's more acerbic editors, a priest named Edward Dowling, commented: "The two greatest obstacles to democracy in the United States are, first, the widespread delusion among the poor that we have a democracy, and second, the chronic terror among the rich, lest we get it."

Six decades later, many illusions and fears are helping to sustain the two-party system. At times, along the way, poll numbers are cited to justify constricting public discourse.

We're told that Nader should not be in the debates because his support isn't high enough among voters. But sometimes, the popular will is flagrantly ignored: Polls consistently show that most Americans would like to see leading third-party candidates included in the debates. But, we keep hearing, that won't happen -- because Americans don't want those debates cluttered with any candidate other than Bush and Gore.

Isn't the two-party system wonderful?

Norman Solomon is a syndicated columnist. His latest book is The Habits of Highly Deceptive Media.