It will surprise few to learn that the big picture often slips unnoticed past Washington’s window.

The tea party movement — organic, angry and thriving — is only the most recent to take insiders by surprise. Out yonder, among shuttered storefronts and leaner lifestyles, the tea party has been a predictable response to supersized government spending and aggressive hubris.

Another movement percolating right in front of our noses seems to be equally invisible to establishment eyes. Independents — neither right nor left, but smack dab in the broad middle — today constitute 42 percent of the electorate, according to a recent CBS/New York Times poll.

Approximately 70 million strong, these are America’s new homeless class, people who are equally disgusted with both traditional parties and the special interests that control them. They’re all ages, sexes, races, ethnicities, though younger Americans are crowding the front rows. Of those born after 1977, 44 percent self-identify as independent.

Independents as a group outnumber either party, in other words. Yet, given the hyperpartisanship that began under George W. Bush — and that has accelerated during President Obama’s first year, thanks in large part to the enabling mechanism of the Internet — one would think that America were divided into hard left and hard right.

We’re not. We’re a vast middle, slightly right-of-center nation. How is it that so many feel so disenfranchised by so few?

I run into the politically homeless everywhere I go. Meet two South Carolina men named Joe, with whom I chatted with over the Christmas holiday. Neither a plumber nor a six-pack, both are successful businessmen and lifelong Republicans now wandering the political desert. Fiscal conservatives alienated by the GOP excesses, they’re equally loath to identify themselves as Democrats.

Fast forward to the University of Pennsylvania where I spoke to a journalism class a couple of weeks ago. I talked a bit about the wingnuttery that has hijacked politics and how some of us who consider ourselves moderates (otherwise known as apostates) have decided it’s time to denounce the harsh partisans who feed on polarization. It’s time to give independents a voice.

This is, of course, a punch line in true-believer circles, where independents are considered squishy and lacking in principled conviction. This has never been true, or else George Washington, John Adams, Thomas Jefferson, Dwight Eisenhower and Ronald Reagan, among others, never would have been president. Reagan probably wouldn’t win his party’s nomination today.

The far left is equally nutty, it goes without saying. For every Pat Robertson, there’s an Al Sharpton, as John McCain pointed out in Virginia Beach in 2000, possibly his best speech ever. But how has this happened? Why have we given the loudest voices so much power when their numbers are so few?

As John Avlon writes in his book, “Wingnuts,” the lunatic fringe may have networks and netroots, “but we (centrists) have the numbers.” Isn’t it time we stand up to the extremes on both sides?

After the Penn class, a female student approached and said in a low, almost conspiratorial voice: “You know, what you said in there? Please do that. Do it soon.”

Centrists — who may be broadly defined as fiscally conservative, socially libertarian-ish — have been relatively quiet as “patriots” have made threats, building armies of “hunters” to bring down RINOs (Republicans in Name Only) and DINOs (Democrats in Name Only), or creating online “Leper Colonies” to post the names of those who, for example, dared speak out against Sarah Palin. The latter was the creation of Erick Erickson, founder of RedState.com, recently hired as a CNN commentator and famous for calling retiring Supreme Court Justice David Souter a “goat-xxxxing child molester,” among other similarly trenchant observations.

Thusly, do hyperpartisans become mainstream.

It’s fine to be angry about bad policies; it’s fine to hold politicians’ (and journalists’) feet to the fire. But it is not fine to demonize dissent and cultivate rage. We should know by now where demagoguery leads.

America’s first popularly elected female senator, Maine’s Margaret Chase Smith, knew — and she bravely faced down fellow senator Joseph McCarthy in 1950 with her “Declaration of Conscience” against hate and character assassination. Twenty years later, on the anniversary of her declaration, she wrote words that resonate yet again:

“It is time that the great center of our people, those who reject the violence and unreasonableness of both the extreme right and the extreme left … shed their intimidated silence and declared their consciences.”

Hear, hear. And, dare I say, mega-dittos.

Kathleen Parker writes for the Washington Post. Her e-mail address is kathleenparker@washpost.com.