Heated immigration hearing previews upcoming battle over Arizona law Hundreds gathered at a rally supporting Arizona's new law on illegal immigration as they listen to speakers near the capitol Saturday, June 5, 2010, in Phoenix. (CBS News) Democrats in the Senate engaged in a pointed debate on Tuesday with the author of Arizona's controversial immigration law, with both sides accusing the other of distorting the facts and failing to serve their constituents. The acrimony on Capitol Hill offered a preview of the political rancor that could erupt later this summer, when the Supreme Court rules on whether that Arizona law is constitutional. The Supreme Court is slated to hear arguments on Wednesday on whether the law, known as S.B. 1070, oversteps the states' authority on immigration law enforcement -- an obligation traditionally left to the federal government. Democratic Sen. Chuck Schumer announced Tuesday that should the Supreme Court uphold the law, he'll introduce legislation on the Senate floor to invalidate it and reiterate the point that Congress does not intend for states to enact their own immigration schemes. "Immigration has not and never has been an area where states are able to exercise independent authority," he said at a hearing held by an immigration subpanel of the Senate Judiciary Committee. "It's simply too damaging to our economy and too damaging to our democracy having 50 states doing 50 things" on immigration. At issue wasn't just the law's practicality. Opponents of the law who testified before the panel said the bill encourages racial profiling and has divided the Arizona community. Democratic state Sen. Steve Gallardo of Arizona called it "the worst piece of legislation ever passed in the state of Arizona." Former U.S. Sen. Dennis DeConcini, a Democrat from Arizona, said, "I'm embarrassed for my state" and apologized specifically to the Latino community. Meanwhile, former Arizona state Sen. Russell Pearce -- the Republican who authored the legislation -- said "the invasion of illegal aliens we face today... poses one of the greatest threats to our nation." He cited the threat of terrorists entering the country illegally, as well as murders on the U.S.-Mexico border carried out by undocumented immigrants. Pearce blasted the Obama Administration for attacking Arizona for "enforcing the law, protecting our citizens, protecting jobs for lawful residents, and protecting the taxpayers and the citizens of this Republic in attempting to secure our borders." Schumer grilled Pearce on a series of controversial aspects of the law: For instance, he asked why law enforcement officials are advised to judge whether a person may be undocumented based on their clothing. What does an illegal immigrant dress like? Schumer asked pointedly. The two sparred over whether the advisement came from U.S. Immigration and Customs Enforcement (ICE). Pearce also locked horns with Democratic Sen. Dick Durbin over whether the DREAM Act provides "blanket amnesty" to undocumented youths. On top of that, the opponents of the bill who testified with Pearce called into question the data he cited to prove the law has been effective. Even before the hearing began, it was a contentious scene: Schumer and Durbin were the only two lawmakers who attended, with Republicans dismissing the hearing as "political theater." Additionally, Arizona Gov. Jan Brewer, a Republican, declined Schumer's invitation to testify. Schumer said Republicans were "absent from this hearing just as they've been absent from every attempt we've made to... solve this problem [of immigration]." While the Supreme Court will hear arguments on the Arizona law's constitutionality on Wednesday, it will announce its ruling sometime in June -- right in the middle of the presidential campaign. Schumer mentioned the praise that Republican presidential contender Mitt Romney has given the law, a sure sign that the GOP contender will be hounded on the issue by Democrats for months to come.