WASHINGTON (CNN) -- Simmering tension between the White House and U.S. Supreme Court spilled into public this week when Chief Justice John Roberts labeled the political atmosphere at the State of the Union address "very troubling."
With six members of the court a few feet away in the audience, President Obama used the occasion to criticize the conservative majority's ruling in a campaign finance case.
Roberts on Tuesday told students at the University of Alabama that such partisanship at the annual address in Congress leaves him questioning whether the justices should continue to attend, as most do, in accord with tradition.
"It does cause me to think whether or not it makes sense for us to be there," Roberts said. "To the extent the State of the Union has degenerated into a political pep rally, I'm not sure why we're there."
Roberts, 55, was among the five justices who ruled in favor of loosening congressionally mandated restrictions on so-called "corporate" spending in federal elections. The decision opened up spending for a range of corporations, unions and advocacy groups.
The White House was quick to attack Roberts indirectly, focusing on the ruling itself, and Obama continued the criticism in his January address, saying, "With all due deference to the separation of powers, the Supreme Court reversed a century of law to open the floodgates for special interests -- including foreign corporations -- to spend without limit in our elections."
Political fallout from the ruling continues. The Senate Judiciary Committee held a hearing Wednesday on legislative efforts to blunt the impact of the court's decision.
Roberts on Tuesday said people have a right to respond to what the courts do, but context should be considered.
"Some people, I think, have an obligation to criticize what we do, given their office, if they think we've done something [wrong]," he said in response to a student's question. "So I have no problems with that. On the other hand, there is the issue of the setting, the circumstances and the decorum. The image of having the members of one branch of government standing up, literally surrounding the Supreme Court, cheering and hollering, while the court, according to the requirements of protocol, has to sit there, expressionless, I think is very troubling."
Members of Congress sat behind the justices at the January 27 address, many applauding when Obama made his remarks about the court's election spending case.
Supreme Court spokeswoman Kathy Arberg said Wednesday that Roberts would have no further public comment on the issue.
Sources close to Roberts said he has grown increasingly frustrated at what he views as the growing partisanship aimed at the federal courts, particularly the Supreme Court.
"The incident at the State of the Union only reinforced his concern the courts have become a political football," said one colleague, who has spoken with the chief justice since the speech.
"He's tried -- publicly and privately -- to reach across the branches and sought to reinforce a level of mutual respect and understanding for their work. He felt like those [Obama's] remarks really hurt what the court is perceived to be doing."
These sources spoke on condition of anonymity since they are not authorized to comment officially on Roberts' behalf.
The chief justice invited Obama and Vice President Joe Biden to a private reception at the court shortly after the two were elected in December 2008. The meeting with the justices was designed as a friendly get-together with the incoming president, a former constitutional law professor.
Justice Samuel Alito was the only one of the nine-member bench not to attend. He was criticized for his reaction to Obama's remark in January. Cameras captured him shaking his head and apparently mouthing the words "not true" as the president spoke.
As a U.S. senator from Illinois, Obama voted against both Alito and Roberts during their confirmation hearings to the high court.
Justices Antonin Scalia and John Paul Stevens have said they do not regularly attend the annual address because of its partisan nature. Scalia has said the justices -- wearing their robes -- are forced to "sit there like bumps on a log" and are not supposed to show any reaction to what is being said.
Roberts also told the Alabama students the process of Senate confirmation of top judicial nominees has become too partisan, criticizing lawmakers who use the hearings to score political points.
"I think the process has broken down," he said.