Republicans pushed the bill to a final reading Tuesday, the last step before taking a vote. But Sen. Chris Larson, D-Milwaukee, suddenly objected to the reading, blocking the vote until the next time the body convened.

Later, Sen. Fred Risser, D-Madison, jabbed the Republicans hard by trying to bring up a bill that would restore collective bargaining for public workers.

Union rights have been a white-hot topic in Wisconsin since Walker introduced a bill last February that erased nearly all public workers' collective bargaining rights. Democrats painted the bill as an attempt to destroy unions, one of their key constituencies. Tens of thousands of people converged on the Capitol on Feb. 15 — exactly a year ago — and launched an around-the-clock demonstration against the measure that lasted three weeks. Senate Democrats fled to Illinois in an attempt to block a vote on the measure, but Republicans ultimately passed the legislation anyway.

Democrats have been looking for payback ever since. They launched recall drives against six Republican senators last summer, ousting two from office. Republicans responded with recall drives against three Democratic senators, but they all survived.