Story highlights Hillary Clinton is ratcheting up her attacks on Bernie Sanders

She says her Democratic primary rival is a "pie in the sky" politician

Green Bay, Wisconsin (CNN) Hillary Clinton has used the last two days of campaigning in Wisconsin to cast her Democratic presidential rival Bernie Sanders as a "pie in the sky" politician making promises he can't keep.

The tactic is one Clinton has revisited time and time again on the campaign trail, but speaks to the fact that Clinton and her campaign are well aware Sanders is likely to do well in the historically liberal state.

The former secretary of state told voters in Madison on Monday that she wasn't a candidate just proposing "pie in the sky stuff" in order to convince people to vote for her.

On Tuesday in Green Bay, Clinton suggested that some politicians that talk about taking on special interests -- something Sanders often does -- are all talk, no action.

"I love it when people talk about taking on special interests and fighting special interests and fighting the powerful," Clinton said. "I mean, those are great speeches. I have done it."

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