Calling him a “constitutional conservative,” Gov. Scott Walker endorsed Sen. Ted Cruz, R-Texas, for the Republican presidential nominee Tuesday.

Walker said on Milwaukee-based radio show WTMJ that Cruz is not afraid to take on special interests and is in the best position to win the general election.

“Looking at speeches, looking at records, looking at what the candidates not only say, but what they have done in the past,” Walker said. “It was an easy call for me to support Ted Cruz.”

Walker plans on campaigning with Cruz in Wisconsin before the primary.

Walker chose to keep his interview “positive” when the show’s host Charlie Sykes asked him about Donald Trump’s campaign.

“I wanted to make sure I was supporting someone,” Walker said. “I wasn’t against something or against someone, but rather for something.”

Gov. Scott Walker formally drops out of 2016 presidential race[Update 9/22]: Following a rapid decline in the polls, Gov. Scott Walker announced Monday he’ll drop his bid for the Read…

After dropping out of the presidential race this past fall and with approval ratings hovering around 40 percent, it is unclear whether Walker’s endorsement will impact voters.

The Wisconsin primary is April 5.