Two members of the Senate Judiciary Committee are asking Supreme Court nominee John Roberts why he did not recuse himself from taking part in a hearing involving the Bush administration when at the same time he was being interviewed by the administration for the justice seat.

Roberts is under fire for failing to recuse himself in Hamdan v. Rumsfeld, a case he decided while serving on the D.C. Circuit Court of Appeals (search). The case involved Salim Ahmed Hamdan, a Yemeni who once was Al Qaeda leader Usama bin Laden's driver. Hamdan challenged the administration's right to try terror suspects being held at Guantanamo Bay, Cuba, before military panels rather than in U.S. courts. The administration won with the three-judge panel finding unanimously in its favor.

At the time Roberts was meeting with White House officials like Attorney General Alberto Gonzales, he was also deciding the case, in which the White House had strong interests since the president was named as a defendant.

Experts say the legal battle should not affect the Roberts fight, but some Democrats smell blood in the water.

Democratic Sens. Chuck Schumer (search) of New York and Russ Feingold of Wisconsin have written to Roberts, demanding to know why he stayed on the case. They argued that since Roberts recently recused himself from a case involving the American Bar Association, presumably because the ABA was reviewing his qualifications for the Supreme Court, then he should also have recused himself in the Hamdan case.

Click here to read the letter (PDF).

"It is clear that you have long understood the ethical issues raised by continuing to work on a case in which a party is considering you for another position," Judiciary Committee Sens. Charles Schumer

"Why did you believe it was appropriate to continue participating in the Hamdan case while being interviewed for a vacancy on the Supreme Court?" the Democratic senators asked in the letter.

The senators cite an opinion from three legal ethics experts, including professor Steven Lubet, who criticize Roberts for not recusing himself.

"I think Judge Roberts at the time he realized he was being seriously interviewed for a Supreme Court vacancy should have stepped aside from the Hamdan case," said Lubet, a professor at Northwestern University.

"Attorney General Gonzales had access to Judge Roberts in a way that council to Mr. Hamdan couldn't even conceivably dream about having," he said.

Sen. Arlen Specter, R-Pa., chairman of the Senate Judiciary Committee, asked another pre-eminent legal scholar for his views on the issue. He received a vindication of Roberts, and of federal judges generally who wish to trade-up their seats on the federal bench.

"These people are getting positions offered all the time and there's never been a requirement they have to recuse or disqualify themselves in cases where the United Staes is a party," said George Mason University law professor Ronald Rotunda.

In fact, Justices Ruth Bader Ginsberg (search) and Stephen Breyer (search), two Clinton appointees, both decided numerous cases involving the executive branch while their Supreme Court nominations were pending.

Lubet said Hamdan is a different situation because the government's interests were so high. Adminstration officials dismiss that rationale as true in many cases.

"It's really an issue concocted out of thin air by opponents of Judge Roberts' nomination to the Supreme Court. And it's unfortunate that we see politics entering into this process," said Deputy Assistant to the President Steve Schmidt.

Lubet says he and his colleagues raised the issue in hopes of convincing the U.S. Supreme Court to review — and possibly reverse — the Hamdan case, not to attack Roberts, whom they say they believe is a man of integrity who voted as he thought the law required.

Roberts' confirmation hearing begins on Sept. 6.