In a 6-0 decision, the court said the fees permitted under the 1999 Check Cashers Act were really triple-digit interest rates. The state constitution limits interest rates on loans to 17 percent.

"Because that fee is in reality an amount owed to the lender in return for the use of borrowed money, we must conclude that the fees authorized clearly constitute interest," Justice Paul Danielson wrote.

Through a payday loan in Arkansas, a customer writing a check for $400, for example, typically would receive $350. The lender would keep the check for about two weeks before cashing it.

The customer could buy back the check for $350 during that two-week period, but otherwise would pay the full $400 when the company cashed his check. The $50 charge on a $350 loan for 14 days equates to 371 percent, well above Arkansas' usury limit.

Attorney Todd Turner, who represented the plaintiffs who challenged the Check Cashers Act, said the ruling means it will be impossible for payday lenders to operate in the state.

"It's great for all the Arkansas residents who have been paying 600 percent for these loans," Turner said.

Tom Hardin, attorney for the Arkansas Financial Services Association that sought to preserve the law, did not immediately return a call seeking comment.

Even before Thursday's ruling, the number of payday lenders in the state has dwindled in response to threats of lawsuits from Attorney General Dustin McDaniel. An advocacy group said in a report last month that the number of payday lenders operating in the state has dropped from 237 in March to just 33.

In its 6-0 decision, the court overturned a Pulaski County judge who last year ruled that the 1999 act was constitutional.

The pop duo's lawsuit says they learned in April 2007 that an unidentified singer-songwriter had used "Maneater" in a 2006 recording.

The papers, filed in Manhattan's state Supreme Court, claim Warner/Chappell Music Inc. breached its publishing contract with Hall and Oates by refusing "in bad faith" to sue for copyright infringement.

The singers seek unspecified money damages and want to terminate their agreement with Warner/Chappell.

A Warner/Chappell spokesman did not immediately return a call for comment on Thursday.

Hall and Oates' hits, which came mostly in the 1970s and '80s, also include "Rich Girl," "Private Eyes" and "I Can't Go for That (No Can Do)."

The justices declined, without comment, to consider the constitutionality of a voluntary program passed by the Legislature and that took effect in 2004.

The program provides campaign money for state Supreme Court and Court of Appeals candidates if they agree to fundraising restrictions leading up to the general election. The decision came on the eve of an election in which all but two of the 13 candidates for those seats Tuesday participated in the program.

The decision leaves a federal lower court ruling in effect that upheld the law, which has been a model for other states, including New Mexico.

"This gives supporters of judicial public financing and public financing in general confidence and assurance that the long line of decisions (supporting) public financing ... are still the law of the land," said Paul Ryan, an attorney with the Washington-based Campaign Legal Center, whose group earlier filed a friend-of-the-court brief in support of the law.

Former Supreme Court candidate Rusty Duke and the North Carolina Right to Life Committee sued over the law in 2005, arguing it restricted free speech rights in cases where outside groups or nonparticipating candidates exceeded spending thresholds.

The justices, in an order Monday, accepted the appeal of prosecutors in Alaska. They asked the court to overturn a federal appeals court ruling in favor of William Osborne, who was convicted of rape, kidnapping and assault in an attack on a prostitute in 1993.

The woman was raped at gunpoint, beaten with an ax handle, shot in the head and left for dead in a snow bank near the Anchorage International Airport.

Osborne admitted his guilt under oath to the parole board in 2004. Another man also convicted in the attack has repeatedly identified Osborne as having participated in the crimes. The testing would be done on a condom and hairs found by investigators.

The 9th U.S. Circuit Court of Appeals, based in San Francisco, said Osborne has a right to subject the evidence to advanced DNA testing that was not available at the time of his trial.

Forty-four states and the federal government have laws that give convicts access to DNA testing, but Alaska does not.

Osborne urged the court to reject the appeal, saying that because so many states have laws on the topic, it rarely arises in federal court.

Prosecutors argued that even if testing determines that the hairs and sperm are not Osborne's, other evidence introduced at his trial is sufficient to leave his conviction in place. That matter is not before the high court.

(CNN) -- A new Republican ad appears to suggest that Barack Obama has al but won the presidential race, an argument several vulnerable Senate Republicans may have to reluctantly embrace with only days until Election Day, an expert in campaign advertising said.

Some Republicans are already planning on a Barack Obama presidency.

Aimed at Kay Hagan, Sen. Elizabeth Dole's surprisingly strong Democratic challenger in North Carolina, the 30-second spot from the National Republican Senatorial Committee warns voters against Democrats holding the White House and Congress, and flatly states that if Hagan wins, the party will "get a blank check."

"These liberals want complete control of government in a time of crisis, all branches of government," the ad's narrator states. "No check and balances, no debate, no independence. That's the truth behind Kay Hagan. If she wins, they get a blank check."

Committee Online Communications Director John Randall denied that the ad is suggesting that GOP nominee John McCain will lose out on the White House.

"The NRSC is not conceding a Barack Obama presidency," he said. "Fiscally irresponsible liberals like Kay Hagan are not the answer in these tough economic times and would only make things worse. Our ad was intended to highlight Hagan's many failings in light of the Democrats' promise to close debate should they control the executive and legislative branches of the federal government."

But with polls warning of a GOP bloodbath November 4, vulnerable senators in red states may have no other option but to suggest that Obama will capture the White House and warn that the Illinois senator needs to be checked by Senate Republicans. Watch more on the fight for battleground states »

"They are basically painting the picture that the presidential race is over," said Evan Tracey of Campaign Media Analysis Group, CNN's consultant on ad spending. "Overall, people prefer divided government. This is that divided government argument: 'Don't hand sole control over to one party.' "

• Past is Prologue: Taking a Hard Look at the Last Administration’s Agenda and Accomplishments
• The Substantive Scope of Section 5 of the FTC Act: Where are the Boundaries and Where Should They Be?
• International Cooperation – Where Do We Go From Here?
• Healthcare Reform – Lessons and Guidance From the Antitrust Front

Programs on Nov. 14 include:

• Transitioning to the Next Administration – What to Expect From the Agencies, the Hill and the States
• Grading the Agencies on Merger Process Reform
• The Rise of Antitrust in the Far East – A Changing Landscape
• The Litigious FTC: FTC Litigation and Administrative Process

For more information about the fall forum visit the section’s Web site at http://www.abanet.org/antitrust.

TheABA Section of Antitrust Law, with more than 9,000 members, is theleading forum for ongoing analysis of policies and developmentsaffecting competition and consumer protection law.

With morethan 400,000 members, the American Bar Association is the largestvoluntary professional membership organization in the world.  As thenational voice of the legal profession, the ABA works to improve theadministration of justice, promotes programs that assist lawyers andjudges in their work, accredits law schools, provides continuing legaleducation, and works to build public understanding around the world ofthe importance of the rule of law.