Congressional Democrats began training their fire on the Supreme Court this week, as the justices opened up a new session that will be stacked with politically charged cases.

Senate Democrats probed Justices Stephen Breyer and Antonin Scalia at a hearing Wednesday on the role of the Constitution in deciding court cases and ethics rules governing the high court, while House liberals continued their assault against Justice Clarence Thomas for failing to report his wife’s income.

While Democrats maintain that their activities are to ensure fairness at the high court, which is expected to consider the constitutionality of President Barack Obama’s signature domestic policy achievement, the health care reform law, Republicans allege the efforts are politically motivated.

“What I hope does not happen is Congress starts trying to intimidate members of the Supreme Court when it comes to doing their job,” said Sen. John Cornyn, a former Texas Supreme Court justice and the current head of the National Republican Senatorial Committee. “As an independent judiciary, I think that would be entirely inappropriate.”

The issue came up at the Senate hearing when Sen. Lindsey Graham pointedly acknowledged the politics surrounding the judicial branch.

“We do have a political person appointing judges, and political people confirm judges. That’s the way it works,” the South Carolina Republican said. Graham is an Air Force Reserve JAG officer.

Still, he warned, “We’re going to gut our judiciary of the best and the brightest if we don’t watch our politics and the way we take care of our judges.”

But as the new court session heats up, along with the presidential election, interest groups and lawmakers continue to weigh in and dismiss any fear of a political backlash.

House Democrats have taken particular aim at Thomas, who they charge violated ethics rules by failing to report the income that his wife, Virginia, earned while she worked at the conservative Heritage Foundation from 2004 to 2007. A group of 20 House Democrats led by Rep. Louise Slaughter (D-N.Y.) last week called on the Judicial Conference of the United States, the governing body for federal courts, to look into the matter. The group also suggested the issue be taken up by Attorney General Eric Holder, and on Wednesday, it made the case that the House Judiciary Committee should also take action.

“We are deeply concerned about recent reports concerning potential ethics violations by a Member of the United States Supreme Court, Justice Clarence Thomas,” Slaughter, Rep. Earl Blumenauer (D-Ore.) and others wrote in a letter to Judiciary Chairman Lamar Smith (R-Texas), asking that he hold a hearing on the matter.

In an interview, Blumenauer said he’s “increasingly disturbed by the information that’s coming out about the increasing appearance of politicization on the part of the court.”

Asked whether he feared his party would suffer political consequences from the latest push, Blumenauer said no.

“I have a hard time thinking the Supreme Court is somehow going to be traumatized by having procedures that require them to follow [the same] procedures as the rest of the federal judiciary,” he said. “I can’t imagine that would spook them and change the outcomes.”

The Alliance for Justice and Common Cause also sent a letter to the Judicial Conference about the same issue. “The conduct of some of the justices calls into question the integrity of the judiciary,” said Nan Aron, president of the left-leaning organization.

The Supreme Court began its new session Monday by taking up a case challenging cuts to Medicaid in California. The line-up of hot-button cases is not expected to slow, including ones that touch on the Americans with Disabilities Act, the Clean Water Act and the constitutionality of the Federal Communications Commission’s ban on indecent content on television and radio.

Still, a suit challenging the health care law will be the main event and could be decided by the court just months before the 2012 elections.

The high stakes of the narrowly divided court came up at a political fundraiser in Rhode Island last week, when first lady Michelle Obama hailed her husband for appointing two female justices and reminded supporters not to forget “the impact that their decisions will have on our lives for decades to come.”

That sentiment appeals to both sides. The conservative Judicial Watch has reviewed the role of Justice Elena Kagan in the health care law when she was Obama’s solicitor general. The group has stayed mum on whether Kagan should recuse herself from deliberations when the court considers the law, but other conservative activists have continued their own drumbeat.

Smith has also looked into the matter, asking Holder to review whether Kagan was involved in building a legal strategy for the health care law. That review is pending.

Tom Fitton, president of Judicial Watch, criticized Democrats for going after Thomas in what he called “a coordinated and unprecedented effort to pressure sitting Supreme Court justices.” Still, Fitton said the debate mostly “is something the American public won’t necessarily follow.”