Anger at Washington is not a mandate for ideological purity.

That’s one valuable lesson from Tuesday night’s primary result in Kansas’s first congressional district. And Representative Tim Huelskamp learned it the hard way.

Huelskamp, a conservative agitator who’s been a thorn in the Republican leadership’s side since coming to Congress in the tea-party wave of 2010, lost his seat Tuesday to obstetrician Roger Marshall, who campaigned on the message that Huelskamp was representing a rigid ideology rather than the people of Kansas’s “Big First” congressional district.

The message clearly resonated: Marshall won by 13 points, an unusually comfortable margin against an incumbent who has no ethical or legal baggage.