Former White House staffer Ronnie Cho has decided against a congressional run in Arizona, ending speculation about whether he would jump into a crowded Democratic primary in the state's 7th Congressional District.

"I've been planning and looking at what I would have to do to build an organization over five months. Ultimately, there is just too much to do and not enough time to do it, to give myself the best opportunity to be successful in serving the people of this district," Cho told the Washington Examiner on Tuesday. "I've taken this as seriously as I've taken anything."

Cho was formerly the associate director for the White House's Office of Public Engagement.

In early March, sources close to Cho said that the Phoenix native and Arizona State University alumnus was taking calls encouraging him to run in the race to replace retiring Rep. Ed Pastor.

Rep. Kyrsten Sinema, D-Ariz., who represents an adjacent district, was rumored to have considered changing seats and running in Arizona's 7th, but local Latino-American business leaders and political organizers objected, arguing that her candidacy could threaten the heavily Hispanic area's ability to send a Hispanic representative to Washington.

If elected, Cho would have been the first Korean-American Democrat elected to Congress. But he said race wasn't a "major factor" in his decision, and argued that "people in the district want good, positive, effective representation, regardless" of ethnicity.

The first-generation Korean-American warned not to count him out for future political races, however, and is looking to move back to Phoenix in the near future. He still has a 602-area code cell phone and an Arizona driver's license, he said.

In the meantime, Cho will continue his work with Jim Steyer's Common Sense Media to connect American classrooms to broadband.