It's a political perfect storm: The pairing of a government shutdown with the rollout of a big chunk of the health care law is illustrating all sorts of partisan and cultural tensions that are roiling America. Big government vs. small. The Republican Party's identity crisis. Sharpening political divisions among Americans. And plenty more.

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HOW BIG IS TOO BIG?

Dueling images of the government powering itself down just as Americans for the first time are logging on to Obamacare's new health-insurance exchanges bring into high relief a debate that Americans have been having since the birth of the nation. How much government do we really need? How much is too much?

The Founding Fathers rejected the tyranny of kings and apportioned powers among Congress, the states, the executive and the courts in a balance that Americans of diverse beliefs have argued over ever since. Ronald Reagan famously declared government the problem, not the solution — then added to its size. Bill Clinton announced the end of the era of big government — and pared it back. Barack Obama won election — twice — holding out the promise of an activist government that could do so much more for its citizens.

Now, Republicans have turned Obamacare into a political metaphor for what they hold out as the heavy hand of Washington. Sen. John Cornyn, R-Texas, said people in his state are telling him that if shutting things down "is the only way to stop the runaway train called the federal government, then we're willing to try it."

Others question whether it's a fair fight.

"There are no Republicans who talk about Obamacare as anything other than socialized medicine, a government takeover of the health care system," says Calvin Mackenzie, a professor of government at Colby College in Maine. "Anybody who's studied Obamacare would find that a hard conclusion to draw."

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GOP SOUL SEARCHING

Sure, there's a huge clash between Republicans and Democrats unfolding in Washington. But the more interesting struggle is playing out within the Republican Party, whose tea party contingent is forcing even conservative members to tack ever farther right and making it harder for Congress to find common ground on all sorts of big problems — not just the budget.

House Speaker John Boehner was reluctant to provoke a shutdown but ultimately bowed to pressure from tea partyers in his caucus insistent on linking the fight over Obamacare with financing for the government.

Obama put the blame for Washington's paralysis all on "one faction of one party, in one house of Congress, in one branch of government." That was an oversimplification, no doubt, but one that summed up the roiling divisions in the Capitol and within the GOP. It laid bare the sense among Democrats that the tea party is not just an opposing force, but a corrosive one.

There are plenty of Republicans who are fine with a government shutdown. But others in the GOP worry that the party is heading for a repeat of the 2012 elections in which GOP presidential candidate Mitt Romney and a number of conservative candidates for Congress didn't have enough appeal with moderates to produce GOP victories.

The standoff over Obamacare could be a moment of truth for a party trying to determine its direction.

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THE HEALTH CARE DILEMMA

The president accuses GOP critics of Obamacare of trying to keep people uninsured; Republicans say they're waging a principled fight against a mammoth government overreach.

Both arguments oversimplify the debate. At the heart of Obamacare are complicated questions of what kind of health care Americans are entitled to, how much they should have to pay and how to rein in the huge share of U.S. economic activity that is swallowed up by health care costs.

Americans spend nearly 20 cents of every dollar on health care.

What worries economists most is the rate of growth. The nation's health care tab has consistently grown faster than just about everything else, outpacing wages and the gross domestic product. That means it could crowd out other priorities, such as business investment and government spending on education.

Government programs cover more than 100 million Americans — about 1 in 3 people. That share is going to grow as Obama's health care law takes hold.

But unlike many other developed nations, the United States seems likely to keep its mix of employer coverage, government programs and individual responsibility instead of adopting a government-run model for all.

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NANNY WARS

The Obamacare debate touches on a long-running debate in America about the idea of a "nanny state" — when the government goes too far in protecting people from themselves.

Does the mandate to obtain health insurance just concern the person who is forced to get it? Or does it benefit the health care system and the economy to make sure nearly everyone is covered? That's part of the debate over the health care law.

Prohibition said no to making and selling booze — in the Constitution, no less, until another constitutional amendment made it easy to get plastered again. Washington pushed for state motorcycle helmet laws, with mixed success, and mandated seat belts in vehicles.

Hillary Clinton earned plenty of ridicule from the right for asserting that "it takes a village" to raise a child. And in the face of substantial childhood obesity, Michelle Obama has taken some hits for her campaign to get kids to exercise and eat healthy food.

Polling suggests that Americans value personal choice over government involvement when it comes to behavior, but it's not quite that simple. In an Associated Press-NORC Center poll out this year, 8 in 10 favored government policies that make it easier for people to make healthier choices, such as providing nutrition and exercise guidelines, and three-quarters supported government money for farmers markets and bike paths. But most didn't like government mandates on their choices.

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RED vs. BLUE

Obama came to national attention almost a decade ago on the strength of a keynote speech to the 2004 Democratic National Convention that rejected the notion of red states and blue states and declared "there's not a liberal America and a conservative America; there's the United States of America." Many times since he's played on that theme of a nation not split by those party colors, in what can only be called wishful thinking.

What's happened in the budget impasse, the struggle over the health care law and much else in Washington is very much a product of red vs. blue, sometimes to a point where each side can barely talk to the other.

Of today's political divisions, Mackenzie says: "They're about as hard as they can be."

Not because the middle ground has necessarily disappeared but because it is not what counts the most to some ideologues at this time. (Check back on that when the 2014 elections roll around). Republicans who have placed their opposition to the health care law at the center of everything are responding only to a slice of public opinion, Mackenzie says. "They're thinking about the people who elect them and the people who fund them and those people are very supportive of what they're doing."

To be sure, bipartisanship is still a feel-good word in Washington, but it's thrown around loosely. Everyone ideally wants the political cover that can come when hefty chunks of both parties agree on something, and they claim it even when it isn't there.

Several Republican lawmakers did just that after a series of polarizing votes leading to the shutdown, particularly the one on the House resolution that sought to pass a budget only on condition that the health care law be stripped of money. Sen. Ted Cruz of Texas claimed a "strong bipartisan majority" in the vote; Rep. Kevin McCarthy of California said: "It was a bipartisan moment because we're all Americans."

It was actually more of a bipolar moment. Only two Democrats voted with the Republican majority and one Republican voted with the Democrats.

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IT'S PERSONAL, TOO

This is a political and policy dispute that's also personal.

The tea partyers' disdain for the president is unrestrained, with talk of impeachment all the rage.

Republicans were quick to re-label the Affordable Care Act as Obamacare to personalize their dislike of the thing.

Even Boehner, typically known for his even keel, did a mocking impression of Obama on the House floor as the shutdown neared, parroting the president's voice in saying: "I'm not going to negotiate, I'm not going to negotiate. I'm not going to do this."

Newt Gingrich, the House speaker who orchestrated the last government shutdown in the 1990s, chimed in Tuesday to say that Obama "refuses to behave like an American president. He refuses to deal with the Congress as his equal, which it is in the Constitution."

Obama complained that House Republicans were "trying to mess with me" by passing a bill to cut off money for Obamacare.

But the president and the Democrats themselves have flung out plenty of overheated rhetoric, referring to Republicans as blackmailers, anarchists, extortionists, and more.

Obama offered assurances, though, that "we're not demonizing the other side."

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Associated Press writer Ricardo Alonso-Zaldivar contributed to this report.

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