It's been a long time since Oregon has seen a politician as ambitious as John Kroger.

He jolted the state's staid political establishment with a meteoric rise to attorney general in 2008. 

He pledged to turn the Oregon Department of Justice from a drowsy law firm into an aggressive weapon for the state's citizens.

He declared war on scam artists, corrupt public officials and polluters. He continued to act like the prosecutor he once was, even when the job often called for a softer touch from the state's top counsel.

Kroger's actual record has been mixed: modest achievements with public embarrassments over high-profile cases. Still, nothing seemed able to halt his continued rise, or his willingness to paper with state with press releases. Despite a growing list of political enemies, he had an easy path to re-election in 2012.

That's why Kroger's announcement Tuesday that he won't seek re-election because of an undisclosed health problem has interrupted one of the most compelling storylines in recent Oregon political history.

"I was shocked," says Trent Lutz, Democratic Party of Oregon executive director. "He was somebody that came in unexpectedly and was ambitious and won in a dramatic fashion. He has been actively involved in building the party at the local and county levels."

Kroger, 45, declined to answer questions Tuesday, announcing his decision in a press release from his campaign office.

"I was recently diagnosed and am under the care of a physician at OHSU for a significant but not life-threatening medical condition," Kroger's statement said. "It will not interfere with my legal work or prevent me from completing my term, but I will need to reduce my hours, travel less, and be careful about my health."

The announcement raises more questions than it answers. 

If Kroger won't tell citizens what's wrong with him, how do they know he's healthy enough to serve out his term? How can the most ambitious politician in Oregon be so ill that he cannot continue a campaign but still be able to serve for the next 14 months? What ailment would be sufficiently private that the man whose favorite word is "transparency" declines to say why he's giving up?

A skilled and prolific communicator, Kroger has now created a vacuum which his many critics and enemies will fill to overflowing.

Kroger acknowledged in an interview with the Salem Statesman Journal editorial board Sept. 21 he had already angered many people while doing his job. "The way for someone in American politics to stay out of trouble is to do nothing," he said. "Every time you try to do something, you're either going to anger some people or you're gonna run a risk that you're not going to achieve what you set out to do."

Kroger had already raised $350,000 for his re-election campaign, and no serious candidate seemed ready to take him on. Most people thought he had a good shot at the governorship or the U.S. Senate someday.

In 2008, Kroger, then a little-known professor at Lewis & Clark Law School, stormed into office on the strength of a life story he told in his brisk and compelling memoir, Convictions. After growing up in Houston, he joined the Marines, then graduated from Yale and Harvard Law School.

He learned politics as a campaign aide to Bill Clinton and staffer for Sen. Charles Schumer (D-N.Y.). As a federal prosecutor, Kroger went after mobsters, drug runners and Enron executives. He came to Oregon as a professor at Lewis & Clark in 2002.

Kroger campaigned for attorney general in 2008 on a pledge to shake up the Oregon Department of Justice. Heavily funded by public-employee unions angry at his opponent, former state Rep. Greg Macpherson, he won 56 percent to 44 percent.{::PAGEBREAK::}

Nearly three years into his term, Kroger has indeed shaken things up, although not always with a positive result. He told the Statesman Journal editorial board he considered his biggest accomplishments the consumer protection actions he's taken against more than 100 companies, his efforts to combat drug traffickers, and cracking down on child porn and Internet crimes against children.

"I'm saddened by John's departure from public service," says Dwight Holton, the former interim U.S. attorney for Oregon and close friend of Kroger’s. “He’s been innovative, creative and effective.” 

Kroger has nabbed some misbehaving public officials, chasing the sheriffs of Marion and Jefferson counties from office; pushing a Marion County judge from the bench and knocking prosecutors in Lincoln and Umatilla counties from their posts.

But his performance in higher-profile cases left observers wondering if Kroger was too political. 

The first major case his office handled—the 2009 investigation of Portland Mayor Sam Adams' relationship with a teenaged boy—dragged on for months. In the end, Kroger declined to prosecute Adams, even though the investigation found evidence the mayor tried to tamper with a witness and lied during the investigation.

Last summer, Kroger's office investigated allegations that Oregon Department of Energy employees steered a contract to Cylvia Hayes, companion of Gov. John Kitzhaber. The case brought no charges but plenty of embarrassment to Kroger. His chief prosecutor, Sean Riddell, now faces a bar complaint that he misled witnesses. Kroger later demoted Riddell for deleting key emails in the case.

Kroger's actions also raised questions about his own judgment. He met personally with Kitzhaber to brief him on the still-confidential case and to offer political advice on how Hayes should handle the situation—all while keeping then-Gov. Ted Kulongoski in the dark.

On Monday, Kroger acknowledged a major screw-up. In 2009, the justice department and local prosecutors agreed to dismiss the case against Philip Scott Cannon, who had earlier been convicted of three 1998 murders in Polk County. Cannon won a new trial, but prosecutors claimed they couldn't find key evidence, which led to the dismissal. Recently, four boxes of records prosecutors had thought were destroyed turned up in storage at the justice department.

"Mishandling of evidence is completely unacceptable," Kroger said Monday. "As attorney general, I take full responsibility."

While Kroger's announcement seems to end a promising career, it creates some oxygen for potential rivals such as state Treasurer Ted Wheeler and Secretary of State Kate Brown.

There is also the more immediate question of who will seek to replace Kroger. Although the job provides more visibility and power than any in the state except governor, it pays just $77,200, paltry for lawyers.

The GOP has searched unsuccessfully to find a challenger to Kroger (they failed to field one in 2008). And no Democrat wanted to challenge him.

But on Tuesday, the first name in circulation to replace Kroger was his friend, Dwight Holton.

Holton served as interim U.S. attorney for more than a year until presidential appointee Amanda Marshall was sworn in Oct. 7, raising that office's profile. Holton's close relationship with Kroger may be a mixed blessing. They worked together on the Clinton-Gore campaigns and in the U.S. attorney's office in Brooklyn. 

Reached at the Dallas airport, Holton declined to say whether he will enter the state AG's race. 

Macpherson, Kroger's primary opponent in 2008, says he is considering running. Another name in play is Keith Dubanevich, Kroger's chief of staff.

As potential successors jockey for support, there will be pressure on Kroger to provide more information about his health.

Critics such as former Labor Commissioner Jack Roberts, who as an Oregonian op-ed writer has dogged Kroger's every move, says Kroger should give the public "enough information to reassure us that he can do his job."

“I think when you serve in public office,” Roberts says, “you give up some of the rights to privacy.”