America’s Republicans are typically believed to have moved to the right in recent years, resisting any tax increases and liberal social policies, from gay marriage to immigration reform. House Majority Leader Eric Cantor’s primary election defeat to a more reactionary opponent this week seemed to confirm the theory. Cantor warmed up to immigration reform and was promptly voted out by his constituents.

In this view, President Barack Obama’s Democrats are the only pragmatic and “responsible” party left in Washington. That makes this a very attractive theory for leftists. If Republicans are “far right,” they are centrists by default and can claim to represent Middle America.

The problem with this theory is that Democrats have become just as intransigent as Republicans.

The Pew Research Center finds that the share of Americans who express consistently “conservative” or “liberal” (meaning leftist) opinions has more than doubled since 1994, from 10 to 21 percent. “And ideological thinking is now much more closely aligned with partisanship than in the past.”

Ideological overlap has largely diminished. 94 percent of Democrats are now to the left of the median Republican whereas 92 percent of Republicans are to the right of the median Democrat. Twenty years ago, the figures were 70 and 64 percent, respectively.

Since then, the share of Americans with a highly negative view of the opposing party has also more than doubled. Nearly one in four Democrats has a “very unfavorable” opinion of the Republican Party. 27 percent even see Republicans as a threat to the nation’s wellbeing. For Republicans, the figures are even higher. 36 percent believe Democrats are a threat to American wellbeing.

These strong views lead Americans to erect what Pew calls “ideological silos.” It is not just political life that has become more polarized; it is the whole of life. “Liberals and conservatives disagree over where they want to live, the kind of people they want to live around and even whom they would welcome into their families,” making “blue” states even bluer and “red” ones even redder. Partisanship seems to have become a kind of American tribalism.

Little wonder that politicians have become more left or right wing as well. They are simply responding to the changing attitudes of their most ardent voters.

Politico reported two years ago that Republicans had become “dismissive of any positive role for government that makes the ‘compassionate conservative’ ideas of George W. Bush seem like a very distant echo.” But it also recognized that the Democratic Party was “openly protective of big government in a way it was not during the Clinton years,” evidenced by its wariness of free-trade agreements and resistance to Medicare reform.

Citing Politico, the Atlantic Sentinel argued at the time it was “misleading to berate one party’s vision as ‘extreme’ and say the other’s is pragmatic when it is, in fact, equally ideological and partisan. There is nothing wrong with that. It is why Americans have two political parties to choose from.”

But for the majority of Americans, that choice is becoming tougher. Most of them don’t have consistently left- or right-wing views. According to Pew, “Most do not see either party as a threat to the nation. And more believe their representatives in government should meet halfway to resolve contentious disputes rather than hold out for more of what they want.”

The reason those in the middle are not being heard is that they are the least politically active — “while the most ideologically oriented and politically rancorous Americans make their voices heard through greater participation in every stage of the political process.”