Washington (CNN) — The political furor escalated over President Obama’s high-profile rebuke of a recent Supreme Court ruling on campaign advertising Thursday, as Democrats pounded the high court decision.

Democrats rallied around Obama the day after the president committed a rare breach of political etiquette, criticizing the controversial ruling in his State of the Union address as members of the high court sat only a few feet away.

The court’s 5-4 decision, issued last week, removed long-established legal barriers preventing corporations from spending unlimited sums of money to influence voters in political campaigns. Democrats fear the decision has given the traditionally pro-business GOP a powerful new advantage.

“With all due deference to separation of powers, last week the Supreme Court reversed a century of law that I believe will open the floodgates for special interests — including foreign corporations — to spend without limit in our elections,” Obama told a packed House of Representatives chamber Wednesday night.

“I don’t think American elections should be bankrolled by America’s most powerful interests, or worse, by foreign entities. They should be decided by the American people. And I’d urge Democrats and Republicans to pass a bill that helps to correct some of these problems.”

Justice Samuel Alito, part of the court’s conservative majority, could be seen apparently frowning and quietly mouthing the words “not true.”

Supreme Court justices rarely express any hint of emotion or opinion during the president’s State of the Union speech.

On the Senate floor Thursday morning, Sen. Patrick Leahy, D-Vermont, said the ruling “goes to the very core of our democracy and it will allow major corporations — who should have law written to control their effect on America — instead control America. That is not the America I grew up in.”

Leahy, the chairman of the Senate Judiciary Committee, ripped Alito for what he claimed was hypocrisy in preaching the virtues of judicial restraint while backing a decision overturning decades of legal precedent.

“In his confirmation hearing, Justice Alito … testified that the role of the Supreme Court is a limited role,” Leahy said. “That was then when he was seeking confirmation. This is now.”

A spokesman for the high court had no comment when reached by CNN.

Vice President Joe Biden, appearing Thursday on ABC’s “Good Morning America,” argued Obama “didn’t question the integrity of the court. He questioned the judgment of it.”

Biden called the decision “outrageous” and said “we have to correct it.”

Most Republicans have defended the ruling, calling it a long overdue recognition of First Amendment rights.

Lyle Denniston, a writer for the Web site Scotusblog.com who has covered the Supreme Court for five decades, told CNN he could not recall ever seeing a president rebuke the high court in such a high-profile forum. But Alito’s apparent reaction, he argued, was “quite inappropriate.”

Obama “was talking about the consequences of the opinion,” Denniston said. Once the justices issue a decision, “they really need to let the political branches or the people deal with it as they will.”

Denniston noted that Justice John Paul Stevens, the longest-serving current member of the high court, never attends State of the Union addresses. Attending such a speech, Denniston said, involves the justices in a “political circus” that can damage a justice’s image of impartiality.