WASHINGTON -- Chief Justice John Roberts used his annual year-end report to defend his colleagues' integrity, but that defense did not move prominent critics clamoring for the justices to abide by the same ethical rules as other federal judges do.

In the 16-page report, released on Saturday, Roberts rebuffed calls for the U.S. Supreme Court to adopt the Code of Conduct for United States Judges -- which binds lower courts but not the high court -- and pushed back against partisan demands that Justices Clarence Thomas and Elena Kagan recuse themselves from what may be the term's most controversial conflict, the health care cases slated for oral argument in March.

"I have complete confidence in the capability of my colleagues to determine when recusal is warranted," Roberts wrote.

The chief justice might hope that would be the end of the criticism; he likely knows better.

On Dec. 22, Nan Aron, president of the liberal advocacy group Alliance for Justice, had sent an open letter to Roberts urging him "to address questions that have arisen about the ethical standards governing the Supreme Court." As examples, she cited Justices Antonin Scalia and Thomas' appearance as honored guests and speakers at a recent Federalist Society dinner that doubled as a fundraiser. The Code of Conduct says a federal judge "may not be a speaker, a guest of honor, or featured on the program" of a fundraiser.

"The simplest, most direct approach" to clarify the justices' ethical obligations, Aron concluded, "is for the Court itself to make an explicit public declaration that the Code of Conduct governs justices' behavior and to formally adopt it as the Court's own rule."

Speaking to HuffPost on Tuesday, Aron said that "we did get what we wanted" -- at least partly.

"It's clear that the chief justice felt he couldn't ignore a clamor for discussion of these issues anymore," said Aron.

But Roberts engaged with the Alliance for Justice and others only to tell them that their "observation rests on misconceptions about both the Supreme Court and the Code."

"Because the Code was developed for the benefit of the lower federal courts, it does not adequately answer some of the ethical considerations unique to the Supreme Court," wrote Roberts. Still, he explained that the justices do consult the code as a "starting point and key source of guidance," even if they are not bound to comply with that guidance.

Roberts "failed to acknowledge a need for reform," Aron told HuffPost. "He could have said that we ought to take some action to reassure the public and instead said there's no need for the justices to abide by the Code of Conduct, when, in fact, the record clearly shows that there are problems."

Meanwhile, Carrie Severino, a former law clerk for Justice Thomas, took to National Review Online's Bench Memos blog to support Roberts in what she interpreted as his response to "the usual suspects on the left who seem committed to persuading the public that the Court is some sort of law-free adhocracy where recusal is concerned."

Rather than read Roberts' comments as a call for outside groups to cool down the partisan warfare over the Court, Severino insisted that Kagan "is partially responsible for forcing a very cautious and understated chief justice to make an official statement defending the Court's integrity." Severino, who is now chief counsel and policy director of the conservative Judicial Crisis Network, was referring to the newest justice's reticence when it comes to explaining why her prior service as U.S. solicitor general in the early stages of the health care litigation does not warrant her recusal from the Supreme Court cases.

The rest of the blame, Severino wrote, lies with "the everything-is-political Left apparatchiks who are determined to destroy the conservative justices, especially Justice Thomas, even if that means undermining the Supreme Court's credibility in the process."

Stripped of its bombast, Severino's take on Kagan is strikingly similar to Aron's views on Thomas, whose wife has advocated against the Affordable Care Act's constitutionality.

"We believe that because questions have been raised about [Thomas'] conduct over the past year that at the very least he ought to prepare a memo sharing with the public his views on his refusal to recuse from hearing the health care case," Aron told HuffPost, referring to Thomas' since-corrected omission of the source of his wife's income from several years of his financial disclosure forms as well as his acceptance of gifts from conservative think tanks that frequently submit briefs to the Supreme Court.

Nevertheless, Kagan's and Thomas' silence is in line with the Court's history on recusal. Justices almost never explain why they have chosen to participate in or recuse themselves from cases that may trigger conflicts of interest or appearances of impropriety. A rare exception came in 2004, when Justice Scalia issued a memo, weighing in at 21 pages, explaining his decision not to step aside in a case involving Vice President Dick Cheney after it had been reported that he and Cheney had recently gone duck hunting together.

Still, no memo is likely to change the hardened views of each side's partisans about the justices they have come to target or defend.

Nor are the embattled justices or the chief justice likely to heed these calls from outside the Court's walls. Indeed, the Constitution allows for Congress to regulate the lower courts, but not the Supreme Court, which is set up in Article III as coequal to the legislative and executive branches. Roberts noted in his report that, as "in the case of financial reporting and gift requirements, the limits of Congress' power to require recusal have never been tested," suggesting that the justices could strike down any congressionally imposed ethics rules on the Court.

Message: accept our good-faith, but voluntary, compliance with the ethics rules or else.

Despite such heavy-handed hints, the activists' responses to Roberts' New Year's Eve report shows that the chief failed to stop the criticisms of 2011 from carrying forward into the inevitable outcries the Court will face as it tackles the politically charged cases dominating its 2012 docket.

