Dozens of conservatives and leaders of tea party groups from across Wisconsin sent Gov. Scott Walker a letter Tuesday urging him to "be the hero" and reject Common Core education standards.

The letter signed by 61 people came after Assembly Republicans who studied the standards indicated last week that they were not interested in abandoning them. The voluntary standards, covering English and math currently used by 45 states, were adopted in Wisconsin in 2010.

The goal of the standards, which backers say has been achieved, was to improve instruction and better prepare students for life after school. But critics, many of them conservative Republicans, say the standards are too weak, result in too much data collection about students and amount to the federal government creating a national curriculum.

The Republican National Committee in April adopted a resolution calling the standards an inappropriate overreach. Movements to slow the standards down began in nearly a dozen states this year.

Walker's spokesman Tom Evenson released a statement reiterating Walker's past comments that Wisconsin should set higher, state-specific standards. But Walker has not said what specifically he would want to do or change, nor has he committed to rescinding the standards already in place, as the tea party groups want.

Tuesday's letter cast the issue as the most important Walker will face as governor and argued that testimony presented at the four legislative study hearings held across the state this fall made the case for rejecting them.

"You have the ability to be the hero in this story," the letter said. "The question is, will you choose to rise to the opportunity? Or, will you instead tacitly allow the children of Wisconsin to founder on the rocks of abridged knowledge, empty skill sets, and data mining?"

The letter calls on Walker to force the Legislature to pass a bill undoing the standards.

"It cannot be a middle-way, political solution, Governor Walker," the letter said. The Common Core "must go in its entirety, on principle."

Among those who signed the letter were members of tea party groups including The Wisconsin 9/12 Project in Madison, the Fox Valley Initiative in Appleton, the Green Bay TEA Party, the Greater Milwaukee Patriot Network and the La Crosse Tea Party.

The same tea party leaders who signed the letter were among those who pressured Republicans to create the committee that studied the standards earlier this year.

Schools across Wisconsin have already spent an estimated $25 million implementing the standards, a fact that Republicans who were on the study committee referenced at their meeting last week when they shied away from calling for repeal.

Instead, Republicans indicated last week that they believed the standards could remain in place but would be improved and reviewed in future years.

State Superintendent Tony Evers, who signed a proclamation adopting the standards for Wisconsin in 2010, has said any attempt to change them will end up in court because he believes the Legislature doesn't have the authority to do it.

The standards have been praised by many local school district superintendents and teachers who testified at the hearings that they are better than the state's previous standards.

Education experts long advocated for voluntary national standards, leading to development of the Common Core by a national group of state school officials under the leadership of the National Governors Association and the Council of Chief State School Officers.