Has a primary challenge pulled a candidate one direction or another?

[Proud Liberal Dem]

One of the reasons that I hear some people argue that President Obama should be primaried is that it would help pull him to the left. My question about this is, has this ever happened in the Democratic Party, at least in recent history? What makes it a fait accompli that a primary challenge would move President Obama to the left? I've only seen a few instances of primary challenges from the left in our party and none which drove the candidate (perceived to be more to the right) more to the left.

Did Carter move more towards the left after being challenged by Kennedy? Did Gore's positions change as a result of Bradley's challenge (or, for that matter, Nader's third-party progressive candidacy)? In this past election, Blanche Lincoln, of course, was challenged on the left by Bill Halter but she didn't become more progressive in her positions as a result. In fact, if anything, it only hardened her resolve against progressives (and ultimately went down to defeat).

The only example(s) I can think of in regards to primary challenges moving a candidate one way or another seem to be semi-moderate Republican incumbents trying to placate the extremist teabaggers by moving further to the RIGHT. McCain did it last year when faced with a teabagger in his primary and even the more sensible Lugar seems to be trying to do it now in preparation for next year's primary. Olympia Snowe seems to be trying to do it as well in preparation for a likely teabagger challenge next year.

Are there any recent examples (on any level) on our side where a progressive primary challenger has moved the more moderate/Blue Dog Democrat to the left? Or is moving candidates one way or another politically more of a phenomenon among Republicans? Just posting for the sake of discussion.

[MannyGoldstein]

1. There's a larger consideration

Obama, like Clinton, pulled to the far right after being elected, both embracing the "Who the %$#@ else 'ya gonna vote for, chump?" strategy. This is not only fraudulent, it pushed the Republicans even further to the right to maintain a difference between the two parties.

And here we are.

Candidates need to understand that if they mislead, there will be serious, serious consequences to them, not just to working Americans. There is zero alternative for getting America back on track, the BS needs to stop.

[Donnachaidh]

2. +100000

Consequences. If this doesn't happen what's to say the next guy does even worse with promises?

[pnwmom]

3. All primary challenges do is weaken the incumbent in the general election.

A year of being publicly attacked by other Democrats, before going on to being attacked by Rethugs, won't improve Obama's chances in the general.

History is clear on this. If you want to improve Sarah Palin's chances, then support a primary challenge against Obama. A primary challenge won't help the cause of progressives.

[MannyGoldstein]

4. Remember when disgruntled Kennedy voters voted for Reagan?

Or didn't show up to vote?

Me neither.

Carter's big problem was Reagan's question to voters:

"Are you better off now than you were four years ago? Is it easier for you to go and buy things in the stores than it was four years ago? Is there more or less unemployment in the country than there was four years ago? Is America as respected throughout the world as it was? Do you feel that our security is as safe, that we're as strong as we were four years ago? And if you answer all of those questions yes, why then, I think your choice is very obvious as to whom you will vote for. If you don't agree, if you don't think that this course that we've been on for the last four years is what you would like to see us follow for the next four, then I could suggest another choice that you have."

This will be Obama's problem as well.