The main reason most people don't know today's Republican Party is built on extremism, and therefore don't believe extremism is destructive to our national policy and politics, is because the major media covering the two parties insist on parity between them.So we have monumentally stupid headlines like this one from the National Journal, the most orthodox of mainstream media outlets: " Bernie Sanders and the Democrats' Very Own Tea Party ."Yes, the Vermont senator is running for the presidency from the left. Yes, he's a self-proclaimed democratic socialist. Yes, he wants to raise taxes on the rich, break up the big banks, protect women's rights, and do something, anything, about climate change. And yes, all of these ideas have appeal among a broad spectrum of voters

But no: Sanders is not a Democratic counterpart to Republican extremism, because there is no counterpart to Republican extremism.

Consider data collected by Keith Poole and Howard Rosenthal. In examining congressional voting records, going all the way back to the 1880s, the researchers found that 90 percent of today's Republicans are not moderates while 90 percent of today's Democrats are. According to Christopher Ingraham, who reported the Poole-Rosenthal findings in The Washington Post, there's no equating these scores. "There are plenty of centrist Democrats left in the House," he writes, "but hardly any centrist Republicans."

Remember this the next time someone like the New York Post's John Podhoretz accuses Barack Obama of being "the most left-wing president we’ve ever had." From the perspective of someone way out on the outer-banks of politics, that's not saying much.

Consider too Bernie Sanders' recent joke. During a recent interview on CNBC, he said he could support raising taxes on the rich. “When radical, socialist Dwight D. Eisenhower was president, I think the highest marginal tax rate was something like 90 percent.”

That was no laughing matter to some conservatives. In the 1950s, Robert Welch, the president of the John Birch Society, alleged that Dwight D. Eisenhower, the war hero and former Supreme Commander of the Allied Forces, which defeated Nazi Germany, was "a dedicated, conscious agent of the Communist conspiracy."

Conservative intellectual William F. Buckley saved movement conservatism in its infancy by marginalizing Welch (as he did with novelist Ayn Rand). Welch was just too nutty to be taken seriously.

Seven years after Buckley's death, however, the media competes to see who can take Welch-style paranoia more seriously. Such legitimacy is what you get when you back up conspiratorial inanity with millions in cold hard cash. One of Welch's biggest benefactors was the father of Charles and David Koch, the billionaire industrialists who now underwrite much of the Tea Party.

The media's habit of giving everything equal weight, no matter how insane, is complicit in making the Congress a place where good ideas go to die. Even some House Republicans, that endangered species of pragmatist, are starting to wonder about the point of it all.

Take, for instance, the best of the good ideas, an idea that should transcend everything due to its importance to virtually everyone--infrastructure. According to a recent CNN report, "the problem is massive." Bridges, roads, waterways, you name it. The country's infrastructure is aging badly, and in need of some $3.6 trillion in upgrades, according to the American Society of Civil Engineers.

Yet paying for a project of that magnitude requires generating revenue. The gas tax hasn't gone up since 1993. It goes into a fund that pays for most road construction, but that fund ran dry at the end of May. The government is now borrowing from the Treasury Department to pay for upgrades. That isn't too bad. Interest rates are low. But according to Ohio Congressman Jim Renacci, borrowing a tax increase in disguise. He told CNN recently that drawing from the Treasury adds to the debt and burdens future taxpayers.

How much would it cost?

For the average American driver, about three bucks a year ($2.83), according to Renacci's office. Even so, anything above zero is too much for conservatives who dominate the today's Republican Party. Remember, only 10 percent of Republicans are centrists. So if Renacci is able to find enough fellow pragmatists to join enough House Democrats to raise the gas tax, he says he'll probably face a primary challenge in 2016.