The 2010 midterm election season has been officially underway for almost a month now (Illinois' primary was February 2). But for many on the Left, primary season officially got going today, with the announcement that Senator Blanche Lincoln will face a very credible Democratic opponent in the Arkansas primary. The Republican side of the aisle is already facing open revolt against national-party-selected candidates, from their Tea Party faction. And the news that Lincoln will be challenged means that Democrats may also be fighting some tough battles within their own party, before we even get to the general election season. What it means for each party is not clear year, and won't be until after November's results are in, no matter what happens in the primaries.

But it will be fascinating to watch. Because on both sides of the aisle, the base is angry at the perceived flaws of the parties themselves -- which, more and more, is being directed not only at the national party apparatus, but at individual candidates deemed not sufficiently pure enough by either side's base. This could lead to a lot more gridlock in Washington, due to more fervent (left or right) politicians being elected. And then again, it could backfire. For one side, the other, or both.

This is largely due to the fact that winning a primary isn't the same thing as winning the election. And -- especially in an off-year election -- turnout is usually pretty low (compared to presidential election years). Voter turnout is usually the key to off years. And the voters who most likely turn out are the party's committed base. Even more so in the primaries themselves. So candidates which please the base can win their primaries with lots of enthusiastic voters, but then lose in the general election when a more mainstream candidate might have had the chance to win, especially in "purple" states where there is no overwhelming advantage for one party or the other.

But don't get me wrong, I'm not knocking the system. Primaries are part of the tools of American democracy, and allow party voters to select candidates of their choosing -- which is much better than having party hacks hand-select someone, as it used to be done in much of the country (and still is, in places). For the "out" party in any individual race, it is a chance to "send the party a message" and actually change the course the party sets for the future. For the "in" party, it sends a much stronger message -- that whoever is currently holding the office is no longer acceptable, and needs to be replaced with someone else with a (possibly) better chance of holding on to the seat -- and who will then vote more in tune with what the voters want.

Over on the Right, the Tea Partiers are about to prove their true strength, or weakness. If their strength doesn't live up to their hype, then their primary candidates will lose to Republican regulars. There's a real question, if this point is reached, what the Tea Partiers will then do -- hold their noses and vote for the Republican in the general election, or launch third-party candidacies of their own. Although third parties are seldom taken seriously in presidential elections, they can indeed win statewide elections at times. But, assuming this scenario plays out, it is hard to see how a Tea Party third-party candidacy would win in many general election contests. If the Tea Party candidate can't even win the Republican primary, it likely means they will wind up splitting what would normally be the Republican vote in the general election -- allowing a surprise victory by a Democrat (see: NY-23's special election last year).

On the other hand, if the Tea Partiers' strength has not been overhyped and is, in fact, actually growing stronger day by day, then the Tea Party could take over a large part of the Republican Party itself. The national Republican machine would likely quickly adapt to such an outcome, and rally behind the Tea Party candidates who win primaries. This would drag the Republicans, as a party, even further right. Which may ultimately lose them votes among Independents who usually vote Republican -- but who also may be a little alarmed at the Tea Party candidates and their rhetoric. Overall, however, most political prognosticators are predicting a Republican year. So Tea Party candidates who win Republican primaries may ride this wave into office anyway.

On the Left side of things, the much of the Democratic base is just as furious as the Tea Partiers, albeit for a different reason. The Progressives are fed up with the compromises Democrats have had to make to the Blue Dog faction of their own party. Actually, they are not just fed up, they are incensed at what they see as continued kowtowing to Wall Street and the corporate world by Democrats who should be fighting for the little guy instead. This has mostly translated to voter apathy among Progressives, with the concomitant feelings of betrayal and pointlessness. Why bother electing large majorities of politicians with a "D" next to their name, if they refuse to ever do anything worthwhile, and instead spend most of their time on excuses for not producing better legislation? In other words, what's the point? But this apathy could blossom into fervent support for Progressive primary candidates willing to take on the Corporate Wing of the Democratic Party. As Blanche Lincoln's challenger is going to prove in the next few weeks. What that means in the actual primary or general election, however, is anybody's guess at this point.

The Progressives and the Tea Partiers may have vastly different agendas, but they are in agreement on their main strategy, which can be summed up as: "The Party has lost its way, and lost touch with its roots. WE are those roots. We need to take The Party back, and 'throw the bums out' and rededicate The Party to its core values. We are tired of lip service. We are tired of having our votes taken for granted, and then being forgotten after the election. We are going to choose our own candidates, because it is the only way to save The Party from itself."

The results of all this will likely be messy. Because, in statewide and congressional elections, it often comes down to the skills and aptitude of the individual candidates. And a bad candidate running a bad campaign can cause pundits to read things into the results which aren't really there. A Tea Party candidate winning a Republican primary in Florida may not have much to do with one who loses in Arizona, for example. And winning a primary is no guarantee of winning in November (see: Joe Lieberman). Each race has its own dynamics, and those dynamics may not translate well on the national stage.

It will be interesting to watch, though, for us political junkies. One or two Democratic senators who lose primaries to strong Progressives would send a very loud signal to other Democrats. Likewise Tea Party candidates and Republicans. One major difference between the two groups is that Progressives are an established group within the Democratic Party already, and much of the movement is really nationwide in scope. When MoveOn puts out a plea for an otherwise-obscure candidate in some local race, Progressive donations roll in. The Tea Party movement, however, is newer and more decentralized. In fact, there are quite a few different "Tea Parties" vying for attention within the movement. They have shown strength in focusing donations on individual campaigns as well, but with mixed results so far (the Tea Party movement, remember, is less than a year old). But they're riding a wave of enthusiasm this year, whereas Progressives are in more of a bunker mentality at this point, due to being mostly disappointed with what a Democratic Congress has so far managed to get done and the headwinds Democrats face in the upcoming election.

In any case, this year's primary schedule runs from a month ago all the way up to October (see full list). The biggest clusters of state primaries happen in early June and early September. Tomorrow, Texas will hold a primary which has already seen a savage fight on the Republican side. From now until November (and beyond) much will be said about these races, and many conclusions (most of them wrong, as usual) will be drawn. Will the Republicans capture the House, or will the Democrats hold on to their majority? What will the makeup of the Senate look like next year? Races for governorships and statehouses will have extra weight this year, since it is a census year (meaning redistricting House seats will be up to whoever wins this year, in many states).

Both parties are facing a strong anti-incumbency feeling in this year's election. Or even "anti-Washington." The central party machine on each side has left many in the electorate fed up with politics-as-usual (however they define the term). Both parties will go through a period of redefinition and rededication throughout the course of the election.

Which, as I said before, is a good thing. Political parties need this sort of catharsis every so often, to shake up the moribund system in Washington. Most of the country, after all, lives outside the Beltway. Which politicians always ignore at their peril.

Cross-posted at The Huffington Post

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-- Chris Weigant