WASHINGTON (NewsNation) — The Senate Judiciary Committee is set to review ethics rules for Supreme Court justices on Tuesday as a pair of recent investigations into improper gifts and land deals involving SCOTUS called the rules into question.

Committee members were reportedly at odds over ethics rules for members of the Supreme Court with Democrats believing the highest court in the country should be held to the highest standards, while some Republicans described this as an attack on conservative justices.

This issue shot to the forefront after a ProPublica report revealed Justice Clarence Thomas had not disclosed two decades’ worth of luxury vacations paid for by Republican mega-donor Harlan Crow, who has also bought real estate from Thomas.

Thomas described Crow as a dear friend, saying he didn’t believe he needed to disclose those vacations.

Then, just last week, Politico released a report that Justice Neil Gorsuch had not disclosed the identity of a person who bought property from him in Colorado.

That person ended up being the head of a law firm with several cases before SCOTUS.

As part of this hearing, members invited Chief Justice John Roberts to testify, but he declined to do so.

“Testimony before the Senate Judiciary Committee by the chief justice of the United States is exceedingly rare, as one might expect in light of the separation of powers concerns and the importance of preserving judicial independence,” Roberts said in a statement.

Roberts also addressed how justices must follow court ethics and how it is up to each justice to decide on any recusals for the cases.

But this issue has led to conflict between Judiciary Committee Democrats and Republicans.

Sen. Dick Durban (D-Ill.), the Democratic chairman of the committee, posted to Twitter, saying, “The Chief Justice’s Statement on Ethics Principles and Practices raises more questions than it resolves. Today, we are asking the Court for answers that will inform our hearings and legislation. As we have said, if the Court won’t reform its ethics standards, Congress must.”

But Republicans continue to question the intentions of the hearing.

Sen. Mike Lee (R-Utah) retweeted a post on Twitter that included a list of SCOTUS-related stories that have broken in the last few weeks. In his post, Lee wrote, “Senate Democrats will try to add to those stories next week in a Judiciary Committee hearing designed to undermine the legitimacy of the Supreme Court.”

“What radical leftists can’t accomplish through the political process—because voters disagree with them—they do through the courts. When the courts push back, they attack the courts,” Lee continued.

However, the recent allegations against the justices have led lawmakers to want the high court to adopt new ethical standards.

A new bipartisan bill from Sen. Susan Collins (R-Maine) and Sen. Angus King (I-Maine) aims to force the Supreme Court to adopt a code of ethics for justices within a year and designate someone to handle complaints.

“There are no ethic guidelines, guardrails, at the highest court of the land. This seems ridiculous,” Sen. Ben Ray Lujan (D-N.M.) said.

Sen. Alex Padilla (D-Calif.) added, “As they’re working to strip away basic rights they’re also failing to hold themselves accountable for some common sense ethical standards.”

In an interview with NewsNation, Sen. Ted Cruz (R-Texas) slammed Democrats for questioning Thomas’ ethics.

“This is all garbage, this is left-wing and frankly racist hatred of Clarence Thomas,” Cruz said.

Testimony on Tuesday will include a law professor and former U.S. Attorney General under President George W. Bush, Michael Mukasey. 

The hearing is expected to kick off at 10 a.m. ET on Capitol Hill.

Nexstar’s Alexandra Limon contributed to this report.