Walker's Over-Reach, Ctd

Dick Morris's latest poll shows Wisonsin voters where the Dish is - in favor of Walker's specific requests of public sector unions, but unwilling to remove most collective bargaining rights. By slipping this collective bargaining provision into the bill - something he did not campaign on - Walker has blundered. Moreover, this measure would presumably be the most fatal to his opponents anyway:

By 54-34, Wisconsin voters support ending the automatic deduction of union dues from state paychecks and support making unions collect dues from each member.

In a poll reliant on Rasmussen's pro-GOP skewed sample, we get the following result:

More than half (56%) of respondents said Wisconsin state workers should have collective bargaining power. Just 32% sided with Walker and said state workers should not be allowed to collectively negotiate benefits and other compensation.

Almost identical. Why doesn't Walker concede on collective bargaining, declare victory and move on?