Pew Research polled that the public unions have a favorable rating in public opinion.  However, Quinnipiac’s poll suggests something a bit more nuanced:

Looking at the controversy over pay for government workers, 35 percent say the pay is “about right,” while 15 percent say it is too little and 42 percent say it is too much.

To reduce state budget deficits, collective bargaining for public employees should be limited, 45 percent of American voters tell the independent Quinnipiac (KWIN-uh-pe-ack) University poll, while 42 percent oppose limits on collective bargaining. But voters say 63 – 31 percent that government workers should pay more for benefits and retirement programs.

Efforts by governors to limit collective bargaining rights are motivated by a desire to reduce government costs rather than to weaken unions, voters say 47 – 41 percent.

Enter Rassmussen on the apparent discrepancy:

Quinnipiac put the collective bargaining rights dispute in context as a potential way to reduce the state budget deficit. Pew described the entire issue as a collective bargaining dispute and never mentioned the state budget deficit. When the deficit is mentioned, the governor does much better; when it’s all about limiting collective bargaining rights, the unions do better.

What does this mean?  Politics is about deliberation over the public good.  In looking at such things, the entirety of the argument is before the public, not limited single issues.  Pew’s poll is limited for it does not capture the entirety of the debate over the collective bargaining power public unions enjoy, and the real problem with the budget deficit in Wisconsin.