Everyone in Washington is swooning over Illinois’s new Democratic senator, Barack Obama. He hadn’t even been sworn in when he made the cover of Newsweek. Mr. Obama may indeed be destined for political stardom, but before Obama fever fully takes hold it’s worth noting how little national attention has been given to the senator he’s replacing: Peter Fitzgerald. The 44-year-old maverick Republican is choosing to retire after one term in part because his brave crusade against political cronyism had so alienated key figures in his own party that the GOP state committee actually declined to endorse him for re-election.

The U.S. Senate would not function with 100 members such as Mr. Fitzgerald, who is both self-righteous and a political loner. But it needs some members like him and Wisconsin Democrat Russ Feingold, another senator who sometimes bucks conventional political wisdom.

Mr. Fitzgerald came to Washington determined to do what he could to clean up what the Chicago Tribune calls “the chronic corruption that stains [Illinois] with the image of a Louisiana, a New Jersey.” His chief nemesis was fellow Republican George Ryan, a 64-year-old career pol who was elected governor in 1998, the same year Mr. Fitzgerald defeated Senator Braun, an ethically challenged Democrat. Mr. Fitzgerald said during his campaign that the “great divide” in our government is not partisan but “between those political insiders who use high taxes to support their lifestyles and the rest of us.”

Asked who the insiders were, he bluntly replied: “They’re the Republicrats – the power brokers in both parties who through clout, connections and consulting contracts manipulate our system for personal gain. They have no ideology, yet they are the ruling elites of our time. They are fleecing you, the taxpayer.”

Naturally, Mr. Ryan’s allies didn’t take kindly to such rhetoric. They moved quickly to try to marginalize the new senator. But their efforts were partially thwarted when a year into the new governor’s term a former top aide to Mr. Ryan was indicted for covering up information about the sale of commercial truck licenses. One sale was to an unqualified driver who caused an accident that killed six children. Soon information tumbled out that whistleblowers who had worked for Mr. Ryan had been fired. By early 2001, polls showed that 45% of Illinois voters thought the governor should resign. Mr. Ryan wound up retiring from office the next year, only to be subsequently indicted on corruption charges. His trial begins in March.

Mr. Fitzgerald can take a lot of credit for exposing the sleaze that surrounded both his own party’s governor and the Democratic machine in Chicago. He was the only major Republican figure in the state to demand Mr. Ryan resign. He told me that after President Bush took office in January 2001, he decided that the only way to clean up Illinois was to emulate the tactics that ended Al Capone’s grip on Chicago in the 1930s, by letting out-of-state prosecutors with no ties to the local machine clean out the corruption.

Mr. Fitzgerald insisted on the appointment of Patrick Fitzgerald (no relation),a prosecutor from New York, as the U.S. attorney in Chicago. Patrick Fitzgerald has since issued a flurry of indictments in political corruption probes involving figures in both parties. Last spring, prosecutors seized records linked to a consultant in Democratic Governor Blagojevich’s budget office.

But like many reformers, Peter Fitzgerald got precious little credit. He quickly moved beyond graft to fight what he viewed as “corporate state” special-interest legislation. Unions were furious when he bucked Chicago Mayor Richard Daley’s plan to expand congested O’Hare Airport and instead called for building a new airport near the Indiana border.Business interests were appalled that in 2001 he cast the only vote against the government’s $15 billion post-September 11 bailout of the airlines, even though struggling United Airlines was based in Chicago. “I predicted the airlines would take the gift of taxpayer dollars, live on it and then go bankrupt, and look where we are now,” Mr. Fitzgerald told me.

The senator also refused to join in logrolling lobbying for local projects. In 2001, he labeled an Illinois congressional delegation “wish list” of $600 million in projects being submitted to President-elect Bush a “mega-hog letter.” “The mere fact that a project is located somewhere within the state of Illinois does not mean that it is inherently meritorious and necessarily worthy of support,” he wrote House Speaker Dennis Hastert, who also hails from Illinois. Mr. Hastert called such behavior “grandstanding.” “When you represent a state, one of your jobs is to represent the state,” said John Feenery, Mr. Hastert’s press secretary.

The low point in relations between the speaker and the senator came when Mr. Fitzgerald sponsored an amendment that would have required competitive bidding in the construction of a library honoring Abraham Lincoln in Springfield, the state capital. The senator accused Mr. Ryan of opposing competitive bidding rules so he could dole out the money to political allies with little oversight. “I want Illinois to get a $150 million library, not a $50 million library that just happens to cost $150 million,” he told fellow senators as he launched a brief filibuster against the project.

Mr. Ryan’s office insisted that the competitive bidding rules would have slowed down construction, and they convinced Mr. Hastert’s office to wait out the filibuster and ram the library money through. But Mr. Fitzgerald won a partial victory. Mr. Ryan had been trying to appoint his chief of staff, Bob Newtson, as head of the library. The negative publicity surrounding the project forced Mr. Newtson to withdraw his name from consideration.

Mr. Fitzgerald did more than oppose pork barrel projects. He used his position as a subcommittee chairman with oversight over budget issues to pass a law requiring that federal agencies that spend more than $25 million be subjected to audits. “When I first came into office, the Agriculture Department was missing $5 billion,” Mr. Fitzgerald told the Chicago Sun-Times. “They’ve worked the difference down to $200 million – but it’s still $200 million!”

A former banker who is independently wealthy, Mr. Fitzgerald also charged after what he regarded as anticonsumer practices in business. He attacked the high fees many mutual funds charged investors as “the world’s largest skimming operation,” and helped convince the Securities and Exchange Commission to issue new regulations reforming the selection of mutual-fund directors and encouraging the lowering of fees. He also lobbied the Treasury Department to rein in college savings plans run by state governments, which he said “charge unnecessary fees that erode investor returns.” He was less on the mark with his insistence that Treasury adopt rules mandating that corporations expense stock options.

Despite all his crusading, Mr. Fitzgerald never won the kind of respect the national press showered on his fellow maverick John McCain. He was a frequent ally of Mr. McCain, who called him “a stalwart in the fight for good government,” but he lacked the senator’s press skill. “Liberal reporters saw me as a conservative with some quirky stands while conservative columnists couldn’t understand my support for prescription drug benefits and blocking oil exploration in Alaska,” he told me.

Some conservatives say Mr. Fitzgerald paid insufficient attention to politics, ignoring party building and skipping political rallies. “If he had been 20% more a team player and 20% less seen as looking out for his own image, he would have made a great senator,” says one head of a conservative think tank. Others say he needlessly antagonized figures like Mr. Hastert and did little to promote his pro-life and socially conservative views. “Peter was motivated by good government,” says David Keene, head of the American Conservative Union. “Because he didn’t have to have a second term in the Senate, he therefore could do a lot of good and leave the heavy lifting on some causes to others.”

In the end, Mr. Fitzgerald simply burned too many bridges to be able to run for a second term. In late 2002, Rep. Ray LaHood, an influential House Republican from Peoria, openly told reporters he was looking for an opponent to challenge Mr. Fitzgerald. Illinois Republican leaders made it clear that he would have trouble raising money for re-election and would have to spend several million of his personal fortune in any campaign. In April 2003, Mr. Fitzgerald decided he would exit the political stage.

Nonetheless, Illinois Republicans, still reeling from the aftereffects of Ryan-era corruption, will be lucky if they can coax Mr. Fitzgerald back into politics after his children are grown. “He was our greatest senator since Everett Dirksen,” says Chicago Sun-Times columnist Tom Roeser. “My fear is that he won’t find a business opportunity in Chicago and will move to some other state, where he would be a great treasure.”

The notion of prophets being viewed without honor in their native land is an ancient one, stretching back to the book of Mark in the Bible. Here’s hoping that tradition doesn’t hold true this time. While residents of Illinois celebrate the remarkable rise of Mr. Obama they should also recall how much better their state is for the fact that Peter Fitzgerald didn’t give a damn if he was re-elected senator.

Mr. Fund is author of “Stealing Elections: How Voter Fraud Threatens Our Democracy.” To subscribe to the “Political Diary” e-mail newsletter featuring Mr. Fund, please visit www.OpinionJournal.com, from which this column is excerpted. © Dow Jones & Company Inc.