CEDAR RAPIDS, Iowa — Ron Corbett, the Cedar Rapids mayor and former Iowa House speaker, said Tuesday he will challenge Gov. Kim Reynolds for the Republican nomination for governor, saying it’s time for new leadership in Iowa.

Corbett, 56, told supporters his campaign would outline plans to tackle some of the state’s most pressing challenges, from the tight state budget to its polluted waterways. He said he hoped to do for Iowa what he had accomplished in Cedar Rapids, where he’s widely credited with helping residents get back on their feet after a devastating 2008 flood and rebuilding major parts of the city.

“We have an opportunity for a new game plan,” the former college football player told supporters from an outdoor stage in the NewBo neighborhood, which was among the hardest hit but now features new businesses. “It is today in this resilient city of Cedar Rapids that I stand proudly and announce I will be running for governor of the great state of Iowa.”

Corbett, who has served as mayor since 2009, introduced himself to statewide voters as a “conservative Republican with an independent streak.”

The announcement sets up a one-year campaign for the June 2018 GOP primary featuring Iowa’s first female governor and the popular mayor of the state’s second largest city. Several Democratic candidates are also running for their party’s nomination in what they see as a winnable race. The campaign is expected to be closely watched nationally because Iowa has trended Republican in recent years.

Reynolds became governor last month when her political mentor, longtime Gov. Terry Branstad, resigned to become the U.S. ambassador to China.

She starts as the favorite in the primary, with strong backing from the party establishment, including its social conservative base and business interests. Reynolds has $1 million in her campaign fund and plans to double that by the end of the year. She has tapped acting Lt. Gov. Adam Gregg as her running mate and this week released a list of 1,050 supporters in all 99 counties.

But Corbett argued that it’s time to turn the page from the Branstad era. He said the administration’s budgeting practices were creating “chaos and unpredictability” and that Branstad’s decision to privatize Medicaid two years ago was hurting the poor and disabled, who are facing cuts and delays in services.

He said he would push to simplify Iowa’s tax code by reducing rates while eliminating deductions, revitalize Iowa’s once top-ranked public schools by improving teacher pay and seek to implement a sales tax increase that was supported by voters in 2010 to fund environmental programs.

Iowa Democrats welcomed the news that Reynolds would face a serious challenger from within her party.

“This primary will leave the Republican nominee out of touch and weakened in 2018,” party chairman Derek Eadon said.

Party Chairman Jeff Kaufmann said the GOP has been “fortunate to have a Republican mayor in one of our large urban areas,” saying Corbett has served the state well. He said he would be neutral but continue to strongly support Reynolds in her capacity as governor, adding that primaries “are not a bad thing.”

Corbett had traveled the state in recent months to promote his new memoir, “Beyond Promises,” which recounts stories from his career in the Legislature, as president of the Chamber of Commerce in Cedar Rapids and his two terms as mayor.

Corbett served in the Iowa House from 1987 until 1999. He was House speaker during his final five years in office, helping push an income tax cut through the Republican-controlled Legislature.

Corbett returned to politics to run for mayor in 2009 as Cedar Rapids tried to rebuild from a flood the prior year that destroyed thousands of homes and businesses. He was introduced Tuesday by resident Linda Seger, who recalled how Corbett helped her and many others who’d lost their homes.

“This was the leader we needed to turn ourselves around,” she said. “This man was so passionate about what he was doing.”