It's often said only two things can be found in the middle-of-the-road: yellow stripes and dead armadillos.

And so it seems in American politics these days.

Whether we like to admit it or not, both major parties are increasingly devoid of moderating voices that help keep them from slipping over the edge into an ideological abyss that often spells d-e-f-e-a-t at the polls and g-r-i-d-l-o-c-k in governance.

Don't misunderstand me: I'm an unabashed liberal who thinks the state and nation would be far better off if we embraced a truly progressive agenda. But I don't want to be lumped into Barry Goldwater's extremism in the defense of liberty is no vice-camp, either.

It's difficult not to see just how polarized our politics are when you watch the state Legislature and Congress tinker around the edges of really big problems facing our state and nation, rather than putting aside partisan zealotry in order to produce visionary solutions.

We're all Americans? We're all Oklahomans? Baloney. Win-win is out, scorched earth is in -- a winner-take-all approach honed to a fine art by the Lee Atwaters and Karl Roves of the world.

This rant isn't early summer navel gazing. It's pertinent in light of Oklahoma Rep. Dan Boren's recent announcement he would not seek a fifth term next year.

Boren is the state's lone Democratic congressman, but he's no liberal. In fact, I'm not certain he can even spell the word most days. He's a real-life middle-of-the-roader, a politically endangered species on the verge of being purged by both parties.

Remember when there were Rockefeller Republicans? They called themselves "fiscal conservatives with a social conscience." They played a prominent role in the GOP -- some, like former Gov. and U.S. Sen. Henry Bellmon, helped break the Democratic stranglehold on Oklahoma.

No way, no how a Henry Bellmon-style Republican could win the nomination these days in Oklahoma -- not socially conservative enough. Heck, even former U.S. Sen. Don Nickles -- once considered so far right you needed a telescope to find him -- probably would have a difficult time appealing to the zealots that dominate low turnout GOP primaries in Oklahoma.

Is Boren the poster child for similar rumblings on the Democratic side?

Boren is one of Congress' most famous Blue Dog Democrats, a moderate-to-conservative group of mostly southern members who vote almost as often with the Republican congressional agenda as their own party's. Boren easily beat back a challenge from the left -- state Sen. Jim Wilson of Tahlequah -- in last year's Democratic primary, but it cost him $1 million to do so. And then in a general election marked by an anti-Democratic tsunami, he won re-election with less than 60 percent of the vote -- a much tighter fit than in his previous three races.

Progressive Democrats and ultra-conservative Republicans both smelled blood: Democrats were persuaded voters in Oklahoma's 2nd Congressional District would sooner vote for the real thing than "Republican lite;" Republicans were just as convinced the red state tidal wave finally, inevitably was seeping into Democratic-dominated eastern Oklahoma.

Which leaves both parties grappling with a particularly vexing question: Would you rather nominate an ideologically pure candidate or a more moderate standard-bearer with a better chance of winning?

Before I'm accused of setting up a false dichotomy, I want to make it clear: I'm not suggesting it's either-or, period. I'm just pointing out the obvious: Americans generally -- generally -- have rejected those they consider to be on the political extreme (though some in Oklahoma might point to Democratic Rep. Dennis Kucinich or GOP Rep. Michele Bachmann as exceptions to my premise). It's certainly true that hard-lines from either end of the ideological spectrum find it nearly impossible to win the higher they climb on the political ladder.

Maybe it's better to pose the question this way: Would you prefer to compromise some of your core political principles in order to secure a half a loaf -- or would you prefer to remain ideologically pure and collect no loaf?

It's a difficult question, even for someone like me, who's covered the sausage making up close for more than three decades. And that's why the Boren case is so instructive for both parties.

Boren drove progressives batsh*t crazy when he refused to endorse Barack Obama, his party's own standard-bearer; when he voted against health care reform; when he voted to allow guns in federal parks; when he voted against protecting gays from hate crimes; when he ... oh, you get the idea.

But what's less known is that for all the talk about his Blue Dog baying and his standing up to San Francisco liberals like Nancy Pelosi, Boren was often a reliable Democratic vote -- in excess of 70 percent at one point during his congressional career.

Overall, his numbers through 2010 were like an armadillo in headlights: the House's 247th most liberal and 179th most conservative member, according to the National Journal -- in other words, slightly right of center overall.

On economic matters, he was 43 percent more liberal and 57 percent more conservative than his colleagues as a whole. On social issues, he was 41 percent more liberal and 59 percent more conservative than the rest of the House. On foreign affairs, he was nearly 50-50 -- 48 percent more liberal and 52 percent more conservative than his 534 counterparts.

So if you're liberal, are you better off with middle-of-the-road Boren or with a clone of the rightwing Republicans controlling the other six seats in the Oklahoma delegation? Boren, of course. But that doesn't mean you can't find a viable candidate -- even in red state Oklahoma -- who could better represent your priorities.

The GOP is facing similar choices -- even in Oklahoma where it now controls all levers of state government power. Some Republicans elected to the Legislature in last year's red tsunami are doing their party and state more harm than good, espousing hate-filled rhetoric and promoting an ideology so extreme that it often makes Oklahoma a laughingstock in the wider world. It should come as no great surprise, then, that some GOP insiders are quieting searching for challengers that can knock off these knuckleheads in next year's primaries.

Zealous liberals haven't necessarily been blown away by Obama: Escalating the Afghan war? Bowing to corporate pressure not to impose strong, new consumer protections in the wake of Wall Street's meltdown? Backing away from single-payer national health insurance? Are you kidding me?

But consider the alternatives -- Bachmann, Palin, Gingrich, Pawlenty, Romney, perhaps even Perry -- and I suspect most liberals would conclude: Obama ain't so bad, after all. In fact, it's not even close: a half a loaf (or less) with Obama is better than crumbs (or worse) from any of GOP's ultra-conservatives.

What this means for Oklahoma's 2nd Congressional District is anybody's guess. Just don't be surprised if one party -- or both -- ends up nominating a candidate that's far from the political mainstream.

-(Arnold Hamilton is editor of The Oklahoma Observer; okobserver.net)