Story highlights Donald Trump kicked off his Wisconsin campaign on the attack Tuesday

The Republican front-runner knocked Wisconsin Gov. Scott Walker

Janesville, Wisconsin (CNN) Donald Trump kicked off his Wisconsin campaign on the attack Tuesday.

The Republican front-runner knocked Wisconsin Gov. Scott Walker and the state's economy under his tenure, just hours after Walker endorsed Trump's chief rival Sen. Ted Cruz of Texas.

"He certainly can't endorse me after what I did to him in the race, right?" Trump said, calling attention to his attacks on Walker before the Wisconsin governor dropped out of the Republican presidential race last fall.

Trump accused both Walker and Cruz of supporting the Trans-Pacific Partnership trade deal that was approved on a bipartisan basis. Both Cruz and Walker supported granting Obama fast-track authority to negotiate the deal, but Cruz ultimately voted against TPP in the Senate.

But Trump focused the brunt of his attacks on Walker by pointing to economic hardships in Wisconsin, which Trump attributed to free trade deals that Trump said have siphoned jobs out of the state to countries like China and Mexico.

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