As his poll numbers continue to sink, Scott Walker is betting everything on Iowa:

Whether there’s another climb up the tracks isn’t likely to be known for weeks or months, as Walker deploys a new strategy that places virtually all his chips on Iowa.

Walker’s campaign is belatedly recognizing that their candidate can’t run as a top-tier candidate because he was never really in a position to be that kind of candidate from the start. It was something of a disservice to Walker to treat him as a leading candidate before he had done anything to earn it, and it made him even more unready to cope with the demands of a presidential run. Like Pawlenty, Walker was promoted to being a top-tier candidate before he had demonstrated that he was one, and expectations were accordingly set far too high. Most candidates have difficulty transitioning from statewide politics to the national stage, and Walker was definitely unprepared for that transition. Unlike many of his competitors, however, Walker didn’t have the advantage of relative obscurity to try to get ready. As a result, he has repeatedly flubbed his answers on national and international issues that he didn’t know very well and hasn’t learned how to cope with the attention and scrutiny that a top-tier candidate receives. His boosters didn’t want to acknowledge his weaknesses as a national candidate, and so their disappointment in him has been even greater than it would have already been, which has probably caused more people to give up on his candidacy sooner. Also like Pawlenty, Walker is now being forced by his woes to scale back his campaigning and to focus even more on one state, and in the event that Iowa doesn’t give him a win it will mean the end of his campaign just as it did for Pawlenty. The main difference is timing: Walker’s agony will likely be prolonged until next year, while Pawlenty’s candidacy was halted by his anemic showing at Ames.

Update: Walker is reportedly dropping out now.