Ask a politician if they’d rather be voted out of office by their own party’s voters in a primary or by all the voters in a general election. In the latter case, maybe the political winds were just blowing the other way. But in the former case, you’ve been stripped of your political home. That is why primary upsets have more potential to change long-term voting trends, and the behavior of a party, than a party merely getting trounced in an election cycle.

Democrats are facing a political headwind, but Republicans are already in disarray. Basically, there is a whole breed of Republican who feels like they are no longer welcome in the party.

“We can’t be a majority party if we can’t appeal across the spectrum, if we have an exclusionary approach in general,” said Ms. [Olympia] Snowe [R-ME], who considers Mr. Castle a personal friend and was crestfallen by his defeat.

“A 100 percent ideological purity test — I don’t live in that utopian world; it’s not reflective of the real world,” she added. “I hope that’s not the approach.”

For now, however, it most definitely is the approach.

Ms. [Susan] Collins [R-ME], who provided a key vote in support of President Obama’s economic stimulus plan and backed the Wall Street regulatory overhaul, said Mr. Castle’s defeat had come as a shock. She attributed the rise of the conservatives to a backlash against Obama administration policies.

“It is stunning that he could be defeated in a primary, and it is very troubling to me,” Ms. Collins said in the recent interview.

She may be spinning or she may be in denial, but the Tea Party is also a reaction against the Bush administration’s policies. This becomes clear if we pay close attention to what Tea Party standard-bearer Sen. Jim DeMint had to say in yesterday’s Washington Post.

In 2006 and 2008, bailouts, bipartisan support for earmarks and big spending bills no one had read blurred the lines between the Republicans and Democrats. But after Barack Obama was elected president, Washington’s economic policies went from bad to worse. In a short time the Obama White House and the Pelosi-Reid Congress have made clear that they intend to push America to the left of Europe.

Americans quickly realized that if this country was going to survive, they needed to elect people who would respect, not ignore, the limits of government prescribed by the Constitution. I vowed to do all I could to help. The Senate Conservatives Fund, which I chair, was designed to do just that. I knew in my heart that the Republican Party could save this country if it could recruit more members to stand up for the principles of freedom.

The Americans DeMint is referring to are the Republican primary voters. They are the ones who rejected one Establishment candidate after another in favor of candidates who believe in an extremely limited role for the federal government. In context, DeMint is saying that the Republican Establishment voted for bailouts, abused the earmark process, produced new entitlements (e.g., Medicare Part D), and other large federal commitments (e.g., No Child Left Behind).

It’s important to focus on what the Tea Party advocates. So far, their victims have all been Republicans. So, Susan Collins should keep in mind that it isn’t just a reaction to the Obama administration’s policies that is driving this purge. The Wall Street bailout was requested and signed into law by the Bush administration. The Bush administration ran up the deficit long before Obama came into office in an economy that was shedding over a half million jobs per month. Sen. DeMint is trying to assure that no future Republican administration will expand the role of the federal government. In fact, he won’t be satisfied with keeping the status quo. He wants most of what the federal government does to be ruled unconstitutional.

This isn’t a debate about the size of government. It’s a debate about whether the government, as we know it, should really exist. Any Republican who approaches their job as a legislator with the idea that their ideas can help craft more balanced legislation is completely missing the point. This is Government Shutdown-politics, plain and simple.

There’s a kind of inexorable logic behind this kind of movement, and it doesn’t allow for positive governance. It rejects the very idea that the Congress exists to identify problems and craft legislative solutions. The idea of compromise is completely rejected. It isn’t just a matter of Susan Collins and Olympia Snowe having moderate views on social issues. The fact that they think they should engage in the legislative process at all is the real bone of contention.

How would such a party function as a majority? They’d obviously be incapable of producing a budget that a Democratic president could sign. President Obama would have to rent an industrial-size fan to keep his veto-pen cool.

For now, the fallout from the Tea Party movement is limited to an intraparty struggle among Republicans, but that will change after election day if the Tea Party candidates do well. We’ll all feel the fallout, because Congress won’t be able to do its most basic tasks, like providing funding for the government’s agencies.

People may not like their choices, but they definitely will not like what they get if they elect a bunch of DeMint acolytes to six-year terms in the Senate. People will grow disgusted with what they’ve done long before those six years are up. The Republicans’ disarray will be our country’s disarray before long.