President Obama speaks in the Rose Garden of the White House on June 4, where he announced the nominations of, from left, Robert Wilkins, Cornelia Pillard, and Patricia Ann Millet, to the U.S. Court of Appeals for the District of Columbia Circuit. (Manuel Balce Ceneta/AP)

The decision by Senate Democrats on Thursday to change the rules for confirming judicial nominees could dramatically reshape an obscure federal appeals court that renders some of the most influential legal decisions in the country.

The U.S. Court of Appeals for the District of Columbia Circuit — dubbed the D.C. Circuit for short — was at the center of the Senate fight after Republicans had blocked three of President Obama’s nominees to the panel. Those three are now likely to be approved by a simple majority in the Senate.

The D.C. Circuit has outsize importance in national legal disputes and has helped determine rules for credit card fees, precautions at meat plants and whether companies must deliver pensions promised to their workers. It is often described as the most important court in the land after the Supreme Court.

And for the past two decades, the D.C. appellate court has generally been considered favorable to business, skeptical of regulation and supportive of broad executive powers to wage war and ensure national security.

“Exactly the kind of decisions that Republicans love,” said Drew Courtney, of the liberal advocacy group People for the American Way. “And they want to keep it that way.”

It's more than just a rule change: The so-called "nuclear option" will fundamentally alter the way the Senate operates - for good. (Casey Capachi/(In Play))

On Monday, Senate Republicans blocked Obama’s nomination of Robert L. Wilkins, who was confirmed without controversy in 2010 to the U.S. District Court where he now serves and where the D.C. Circuit is also housed. Senate Republicans also halted lawyer Patricia A. Millett from being named to the court in October and did the same with Georgetown law professor Cornelia Pillard earlier this month.

Before becoming a judge, Wilkins was a trial and appellate lawyer in Venable’s securities and white-collar defense practice and was often listed as one of the city’s top criminal defense lawyers. He has been hailed as one of the “90 greatest Washington lawyers of the last 30 years” by the Legal Times and one of the“40 under 40 most successful young litigators in America” by the National Law Journal.

Millett co-heads the Supreme Court and national appellate practice of Washington power firm Akin Gump. During the Clinton and George W. Bush administrations, she served as assistant to the U.S. solicitor general. She has argued 32 cases before the Supreme Court and 36 in appellate courts.

Pillard, a former deputy assistant attorney general and former assistant to the solicitor general, teaches at Georgetown University Law Center. She has argued nine cases and briefed more than 25 in front of the Supreme Court.

In a statement at the White House on Thursday, Obama said Senate Republicans were “standing in the way of a fully functioning judiciary” by denying judgeships to three public servants who can help “protect our national security, look out for working families, keep our air and water clean.”

Republicans argue that the D.C. Circuit doesn’t need any more judges. The current court has eight sitting judges divided evenly between Democratic and Republican appointees. There are also six senior judges, including five GOP appointees, who help decide some cases.

Some conservatives say they fear Obama’s picks will make pro-government, pro-regulation decisions that hurt average Americans.

“President Obama is eager to inflict the same sort of damage on the judiciary that he is inflicting on American health care,” said Ed Whelan, president of the Ethics and Public Policy Center, referring to rollout problems with the Affordable Care Act.

Because of its experience in federal agency law and its jurisdiction in the home of the U.S. government, the D.C. Circuit has become the venue for any company or group trying to appeal a federal agency’s decision or regulation.

“The decisions that get handed down by the D.C. Circuit aren’t the ones everybody has heard of, but they end up affecting everyone,” Courtney said. “It has a lot of complicated cases that decide about things that decide how government will actually work in real lives. Whether that’s contraception, workers’ rights, environmental protection or consumer health, these are decisions that have a huge impact.”

Matt DeLong contributed to this report.