WASHINGTON, July 6 (Reuters) - Over his 30 years in Washington, Chief Justice John Roberts has been difficult to pigeonhole and defied expectations. More than once, he has remade his image.

His crucial vote last week when the U.S. Supreme Court upheld Democratic President Barack Obama's healthcare plan astonished politicians and commentators, left and right. Yet if history is any indication, the 57-year-old chief justice, appointed for life, will surprise again during the course of a legacy that could last decades.

Indeed, the kinds of social policy issues that play to Roberts' true conservatism, such as affirmative action and other race-based remedies are on the agenda for the term that starts in October.

He has been misread before.

In the mid-2000s, he twice came before the U.S. Senate for confirmation, first for a seat on a powerful Washington-based appeals court and then for the helm of the U.S. Supreme Court. The nominee of Republican President George W. Bush both times, he won broad Democratic support with his folksy charm and promises to adjudicate cases neutrally.

But after his elevation to chief justice in 2005, Roberts in quick succession ruled against abortion rights, school integration plans and campaign finance regulations. His onetime Democratic supporters fumed.

Now, many conservative commentators have lined up against the justice whom they vigorously supported in 2005, and on Wednesday, former Massachusetts Governor Mitt Romney, the presumptive Republican nominee for president, disparaged the chief justice in an interview with CBS News. Romney said Roberts' decision appeared "not based upon constitutional foundation" but rather a "political consideration."

Would Roberts worry?

"He might even enjoy that he's being criticized," said Washington lawyer Paul Smith, who has known Roberts since the late 1970s, when they were first law clerks to judges on the New York-based 2nd Circuit and then to justices at the Supreme Court.

Roberts did not respond to a request for an interview last Friday. He is now in Malta teaching a legal seminar.

In one respect, there has been a consistent pattern to Roberts' tenure in the U.S. capital: He has been a shrewd player of his own interests and a strategic operator on the law. His identity has long been entwined with the judiciary, from his days as a young Supreme Court law clerk and then as an attorney pressing his clients' cases.

"I always got a lump in my throat whenever I walked up those marble steps to argue a case," Roberts said in televised remarks from the White House on July 19, 2005, the evening he was nominated to the Supreme Court, "and I don't think it was just from the nerves."

ALWAYS A STAND-OUT

Born in Buffalo and raised in northern Indiana as the son of a steel plant manager and homemaker, Roberts was always a stand-out: the only boy in a family with three girls, a graduate of both Harvard College (in just three years) and its law school, and, in 1980, a rare conservative among the elite band of Supreme Court law clerks.

In January 1981, while a clerk for Justice William Rehnquist Roberts heard Republican President Ronald Reagan's first inaugural address, and in a speech many years later at the Reagan library in Simi Valley, California, the chief justice recalled: "I felt he was speaking to me."

As a Reagan administration lawyer, Roberts helped develop legal positions against affirmative action, busing for school integration and strengthening minority voting rights. Comfortable in the white-shirt, dark-suit world of Washington, Roberts put in long hours and moved up quickly.

He took a turn into private practice and then became principal deputy U.S. solicitor general under President George H. W. Bush, representing the federal government in cases at the Supreme Court.

In 1992, Bush nominated him for a seat on the U.S. Court of Appeals for the District of Columbia Circuit, often dubbed the nation's "second highest court," because of its case load of civil rights, environmental and other regulatory issues, and long a launching pad for Supreme Court justices.

Roberts was 37. That time around, then-Senate Judiciary Committee Chairman Joe Biden, a Democrat from Delaware, declined to schedule a hearing on his nomination. Key Democrats simply believed Roberts was too hard-right. The next year, after Democrat Bill Clinton became president, Roberts moved on to the white-shoe law firm of Hogan & Hartson in Washington. He argued frequently before U.S. appeals courts and the Supreme Court, representing a group of states in antitrust litigation against Microsoft Corp., the National Collegiate Athletic Association in a sex discrimination case and Toyota in a dispute over employee disability benefits. All told, in his work in private practice and as a government lawyer, he argued 39 times before the justices.

By the time the second President Bush won office in 2000 and began choosing nominees to the D.C. Circuit, Roberts was at the top of the list and seemed more confirmable. He was an establishment lawyer, not a conservative crusader.

Even as Democratic senators blocked Bush nominees, such as Miguel Estrada for the D.C. Circuit, Roberts easily made it through the confirmation process in 2003. He was approved by the Senate on a voice vote.

Two years later, he became the chief justice. He was confirmed by a bipartisan majority, 78 to 22, including with the vote of Democratic Senate Judiciary Committee Chairman Patrick Leahy, of Vermont, who was impressed by Roberts' vow that he would call cases like an umpire.

"Judges are like umpires," Roberts told the committee. "They don't make the rules; they apply them."

The bipartisan glow did not last. After the Roberts Court, with the addition, too, of conservative Justice Samuel Alito, who succeeded Sandra Day O'Connor, began reversing precedents on abortion rights and the separation of church and state, for example, Democrats began to complain about Roberts. The criticism reached a crescendo after the court's 2010 ruling in Citizens United v. Federal Election Commission lifted campaign finance limits on corporations.

A RETURN IN OCTOBER

Roberts will return to the public eye on Monday, Oct. 1, the opening day of the 2012-13 term. He and his eight colleagues will then face several cases that, unlike the financing of healthcare, could inspire Roberts' true conservatism.

At the top of the heap are cases on affirmative action, voting rights and gay marriage - issues where he may stay the conservative course or further shatter the conventional wisdom.

From his early days in the Reagan administration, Roberts has sought to roll back the government's use of racial remedies. In a 2006 case involving the drawing of "majority minority" voting districts to enhance the political power of blacks and Latinos, Roberts referred to "this sordid business (of) divvying us up by race." The following year, in a case involving school integration plans, he wrote, "The way to stop discrimination on the basis of race is to stop discriminating on the basis of race."

Next term the justices will review the constitutionality of a University of Texas campus affirmative action program. Given his past sentiment, Roberts could be poised to lead the conservatives in an opinion striking down the program and reversing a 2005 ruling in a University of Michigan case allowing race to be a factor in admissions.

A separate case testing the heart of the landmark 1965 Voting Rights Act is also headed toward the justices. Roberts has signaled his skepticism for a part of the law forcing places with a history of racial discrimination to obtain federal approval before changing any district lines, ballot requirement or other electoral procedure to ensure they do not harm minority voters.

All or parts of 16 - mostly southern - states are covered by the screening requirement, known as Section 5. And when the court heard a 2009 case testing that, Chief Justice Roberts suggested during oral arguments that it was time to lift the civil rights-era requirement.

The court ended up sidestepping the issue in that case from Texas, yet Roberts wrote for the court, "Things have changed in the South." Now, a new set of challengers to the Voting Rights Act, from Shelby County, Alabama, hope that Roberts and the four other conservatives are ready to strike down the key section requiring early approval for new district boundaries, voter identification rules and other electoral changes. The Shelby County challengers said they will appeal to the justices soon.

More difficult to predict is how Roberts, who has yet to cast a vote in a gay-rights controversy, will vote on the same-sex marriage dilemma.

That socially divisive issue has just landed at the court, testing the constitutionality of the Defense of Marriage Act, which bars legally married same-sex couples from obtaining the federal benefits given to heterosexual married couples. The justices could agree in the new term to hear that case, as well as one moving on a separate track from California involving that state's Proposition 8, which barred same-sex marriages.

Some liberals predict the new term will better reveal Roberts' judicial interests, particularly the cases that recall the Reagan era conservatism.

Unlike the social policy battles of the Reagan era, the healthcare dispute arose as a test of the respective powers of Washington and individual states. The challenge in the beginning was driven by today's Tea Party conservatism, not the Reagan Republicanism that first inspired Roberts.

"The vision of the Constitution that shaped him was centered on social issues like affirmative action and race," said Harvard University law professor Mark Tushnet, who has long studied the court. "That's what he cares deeply about."

(Reporting by Joan Biskupic)

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