The Wisconsin capitol remained under siege Sunday, as protesters vowed to stay put until Gov. Scott Walker removes a portion of the state’s budget proposal that will remove collective bargaining for unions. And Monday’s protests are expected to be the largest yet, although union leaders urged teachers to return to schools that were open. Phil Neuenfeldt, the president of the state AFL-CIO, said he expects protests in support of the union to erupt in 38 states Monday, while the hashtag #wiunion became one of the most tweeted topics on Twitter over the weekend. Meanwhile, some lawmakers said they saw Republicans “wavering” on the issue, although GOP leaders dismissed the idea.