Tomorrow is primary day in Indiana, and things are looking very bad for long time incumbent Republican Senator Dick Lugar. Lugar is facing a serious primary challenge from State Treasurer Richard Mourdock who has the backing of the Tea Party and some of biggest spending conservative groups, including the Club for Growth and the National Rifle Association.

According to the Indianapolis Star roughly $4 million of outside money has been spent on the race, and 70% went to Mourdock. Conservatives are trying to make a example of Lugar for not sticking to their orthodoxy and it looks like they will succeed.

The only recent independent poll shows Mourdock with a solid lead over Lugar. The Howey/DePauw Indiana Battleground Poll has Mourdock leading by ten points, with the race at 48% Mourdock – 38% Lugar. This is a huge turn around from just over a month ago, when the same poll had Luger leading by seven in late March. Similarly a poll from last month on behalf the Citizen’s United found Mourdock 44% – Lugar 39%, but it should be noted that Citizen’s United is backing Mourdock. While it is hard to accurately poll primaries that tend to have low and unpredictable turnout, the size of Mourdock’s lead makes him the clear favorite.

If Lugar does fall tomorrow, he will be just the latest incumbent to lose the Republican party’s nomination for not being conservative enough. Last year conservative challengers cost both Bob Bennett (R-UT) and Lisa Murkowski (R-AK) their Republican nominations. Their loses potentially played a role this year in other Republican Senators like Kay Bailey Hutchison (R-TX) and Olympia Snowe (R-ME) deciding to retire instead of dealing with potential primary challenges.

This is why we are getting a more uniform, extreme Republican party where individual members have become less willing to cross party lines. Conservative groups want their Republicans to vote a certain way, are prepared to enforce discipline, and actually have the resources to do so.

Our political parties are becoming more like political parties in other democracies, with members being fairly unified in opinions and mostly voting as a block. There is nothing wrong per se with a democracy that has strong political parties.¬† But as a country we do need to accept that the previous age, in which¬† meaningless party labels made technically “bipartisan” legislation common, is over. It is not coming back.