The missing component in the machinery of American politics has been moderate-to-liberal Republicanism, and the gears of government are grinding very loudly. You wonder if Kansas and Alaska have come up with a solution to this problem.

In Kansas, Democrat Chad Taylor shook up the Senate race by dropping out last week, giving an independent candidate, Greg Orman, a clean shot at the incumbent, Pat Roberts.

At least one poll showed Orman with a 10-point lead over the 78-year-old Roberts in a two-way race. Republicans are so afraid of Orman that Kansas’s Republican (and unabashedly ideological) secretary of state, Kris Kobach, used a technicality to keep Taylor’s name on the November ballot anyway. Taylor is challenging the decision.

In Alaska, Democrat Byron Mallott ended his candidacy for governor and chose instead to run for lieutenant governor on a ticket led by an independent candidate, Bill Walker. By combining forces, Walker and Mallott hope to oust Republican Gov. Sean Parnell.

Because of the revolution in Republican politics spearheaded by the tea party, these should not be treated as isolated episodes. They are both signs that moderates, particularly moderate Republicans, are fighting back.

The safe journalistic trope is that both of our major parties have become more “extreme.” This is simply not true. It’s the Republican Party that’s veered far off center. To deny the fact is to disrespect the hard work of conservatives in taking over the GOP.

By contrast, there are still plenty of moderates in the Democratic Party. They include Sens. Mark Pryor in Arkansas, Mark Begich in Alaska, Mary Landrieu in Louisiana and Kay Hagan in North Carolina. All of them are threatened in this fall’s elections by conservative or right-wing Republicans. Sen. Mark Warner of Virginia is another moderate on the ballot this year, but so far, he seems safe.

On the other hand, outright liberals have been losing primaries in the Republican Party since the late 1960s, particularly in Senate races. In the House, the few remaining liberal Republicans (one thinks of Maryland’s Connie Morella and Iowa’s Jim Leach) were defeated because Democrats in their districts finally decided that electing even Republicans they liked only empowered the party’s increasingly conservative congressional leadership.

As for the Republican establishment, it may have overcome many tea party challenges this year, but it is increasingly captive to the right wing.

This summer, conservative writers Rich Lowry and Ramesh Ponnuru offered an insightful analysis of the tea party-establishment dynamic in an article in National Review appropriately titled “Establishment Tea.” Lowry and Ponnuru argued that the establishment candidates who triumphed did so largely on the tea party’s terms, though the authors put the matter somewhat more politely. “Candidates who make the case that they will fight for conservative ideas, and not just serve time,” they wrote, “can win tea-party support.”

What’s happening in Kansas is particularly revealing of the backlash against the right from moderate Republicans. Although Roberts is not a tea party candidate — indeed, he defeated a tea party challenger in last month’s primary — the Senate race could be influenced by the state’s contest for governor, one of the most important in the country.

Incumbent Republican Sam Brownback has championed an unapologetic tea party, tax-cutting agenda and has sought to purge moderate Republicans who opposed him from the state legislature. Many GOP moderates have responded by endorsing Brownback’s opponent, Democrat Paul Davis. A Brownback defeat would be a major blow to the right.

“The moderates have said, ‘I’m mad as hell and I’m not going to take it anymore,’ ” said Dan Glickman, a moderate Democrat who represented the area around Wichita in Congress for 18 years. In an interview, Glickman argued that the rightward tilt is antithetical to the GOP’s history in Kansas, a state that sent both Bob Dole and Nancy Landon Kassebaum, in her day a leading GOP moderate, to the ­Senate.

“The Republican Party in Kansas was always a heartland, common-sense, moderate or moderately conservative party,” Glickman said, adding that at times, it has had a strongly progressive contingent as well.

Orman has been almost maddeningly disciplined in not revealing which party he would caucus with if he defeated Roberts. With national Republican operatives pouring into the state to save the three-term incumbent’s floundering campaign, the battle will get a lot tougher.

But already, Republicans are learning that the cost of driving moderates away could get very high. What middle-of-the-roaders could not accomplish inside the party, they may achieve by attacking from outside the gates.

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