John Avlon says Sen. Ben Nelson’s (D-NE) retirement announcement is one more sign that centrist politicians are not welcome in today’s political parties.

“There was a time when divided government did not mean dysfunctional government. The presence of conservative Democrats and progressive Republicans helped ensure that cross-aisle coalitions could be formed to find solutions on the most pressing issues of the day, from the Marshall Plan to the Interstate Highway System to civil rights. But with the two parties now starkly polarized along ideological and geographical lines, and inter-party RINO and DINO hunting purges increasingly encouraged, centrists from both parties are becoming a rare breed in Washington.”
Taegan Goddard’s Political Wire