2015年经济学人 国会选举 在任者不可撼动（在线收听）

Congressional elections

Immovable incumbents

The Republican primaries have produced fewer upsets than expected

JUSTIN AMASH, a congressman, represents one of the most conservative parts of Michigan.

Pat Roberts (pictured), a member of the Senate, represents one of America’s most conservative states.

After hard-fought campaigns both men won their Republican Party primaries on August 5th and now look likely to retain their seats. The similarities end there.

Mr Amash, who is 34, was first elected to the House of Representatives in 2010, riding the Tea Party wave that wiped out both Democrats and old-school Republicans.

A staunch libertarian, he has alienated some in Congress with his stubbornness, which has earned him the nickname “Dr No”.

He tried to oust John Boehner as Speaker and was duly punished, losing his seat on the budget committee.

Sensing an opportunity, business-minded Republicans backed Mr Amash’s challenger in the primary, Brian Ellis. But Mr Amash whipped him, winning by 15 points.

Pro-business Republicans have little beef with Mr Roberts, who is 78,

but conservative insurgents were out for his blood. Having served 33 years in Congress (17 in the Senate),

Mr Roberts is the epitome of an establishment Republican. The main charge against him was that he had become too comfortable in Washington.

He admitted frankly that he owned no home in Kansas and visited the state “every time I get an opponent”.

His opponent this time, Milton Wolf, a doctor, was supported by national and local Tea Party groups, but it was not enough in the end.

Mr Roberts won by seven points.

Drawing conclusions about the Republican Party from these results is difficult. For starters, both incumbents faced underwhelming challengers.

Mr Ellis’s campaign was so vicious that Mr Amash refused to take his congratulatory phone call.

Dr Wolf, a second cousin of Barack Obama, ran a cleaner campaign and did better than expected.

But he was tripped up when it was discovered that he had posted X-rays of his patients on Facebook along with crude jokes about them.

The Republican primaries in Kansas and Michigan, and others elsewhere this year, seem to say more about the power of incumbency than anything else.

With just a few notable exceptions—such as Eric Cantor, the former House majority leader,

who lost in June—those already in office have faced down challenges from candidates of all stripes.

Indeed, Mr Roberts’s victory makes it probable that for the first time since 2008 no incumbent Republican senator will lose a primary.

But the campaigns have raised the question of what makes a politician truly conservative, a mantle grasped by nearly all of the Republican candidates.

For Mr Amash it is a devotion to liberty that does not always suit Republican priorities. For Mr Roberts it seems less about ideology and more about partisan loyalty.

Republican leaders in Congress have had a difficult time accommodating these competing visions. Judging by the primaries, their job will not get any easier.