The already crowded field of Republican hopefuls will soon be getting one more candidate with Wisconsin Gov. Scott Walker filing Thursday to enter the presidential race.

“After hearing from countless Americans during the Testing the Waters phase, Governor Walker this morning will file his papers of candidacy with the FEC,” two aides told Politico.

Walker is expected to officially announce his run July 13 in Waukesha, Wisc. The move comes as Democratic leaders head to Wisconsin to tout policies counter to Walker’s legacy. Democratic presidential hopeful Bernie Sanders held a rally in Wisconsin Tuesday where he discussed the important of unions. President Barack Obama is also expected to speak out against Walker’s policies during his visit Thursday.

Walker gained national attention back in 2011 for reforming labor policy in his state. The reforms, known as Act 10, significantly changed the collective bargaining process for most public employees within the state. It also required public unions to hold a renewal vote every couple years to determine if workers still wanted them.

The reforms easily made Walker one of the main targets for local and national unions. Labor unions and their supporters adamantly opposed the reforms and even tried to get Walker thrown out of office with a recall election. Walker is likely to face even more opposition from unions as he heads into the 2016 election.

Republicans in the legislature went a step further in the past year when they passed a law which banned mandatory union dues as a condition of employment. Though Walker wasn’t directly involved in creating the measure, unions blamed him anyways.

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