Maria Sharapova was guilty of "willful negligence" for using meldonium, and international tennis officials were aware that many players were taking the drug before it was banned this year, former World Anti-Doping Agency president Dick Pound said Wednesday.

Pound told The Associated Press that Sharapova could face a ban of up to four years unless she can prove mitigating circumstances to explain her positive test for meldonium at the Australian Open in January.

Meldonium, a Latvian-manufactured drug designed to treat heart conditions, was added to the World Anti-Doping Agency's banned list on Jan. 1 after authorities noticed widespread use of the substance among athletes.

In announcing her positive test at a news conference in Los Angeles on Monday, Sharapova said she had been using the drug for 10 years for various medical issues. The five-time Grand Slam champion and world's highest-earning female athlete said she hadn't realized meldonium had been prohibited this year, taking full responsibility for her mistake.

"An athlete at that level has to know that there will be tests, has to know that whatever she or he is taking is not on the list, and it was willful negligence to miss that," Pound said. "She was warned in advance I gather. The WADA publication is out there. She didn't pay any attention to it. The tennis association issued several warnings, none of which she apparently read."

A federal appeals court will hold a new hearing on whether a Texas voter ID law has discriminatory effects on minorities ? a potential blow to the Obama administration's efforts to fight new ballot-box restrictions passed by conservative legislatures around the country.

A three-judge panel of the 5th U.S. Circuit Court of Appeals in New Orleans ruled in August that the 2011 Texas law requiring 14.6 million registered voters to show picture identification at the polls violates parts of the federal Voting Rights Act. But an order issued late Wednesday says a majority of the full court, which currently has 15 members, voted to hear the case again.  

The order was issued without additional opinion, and a new hearing date hasn't been set.

Texas was allowed to enforce the voter ID law during elections in 2014 and during last week's primary. Supporters say it prevents fraud, but opponents argue its true intent is to make voting tougher for older, poor and minority voters who tend to support Democrats and are less likely to have the mandated forms of identification.

In a statement, state Attorney General Ken Paxton called the order "a strong step forward in our efforts to defend the state's Voter ID laws."

"We look forward to presenting our case before the full Fifth Circuit," said Paxton, a Republican who has been indicted on felony securities fraud charges stemming from actions he took before becoming attorney general in January 2015.

Conservative and liberal groups are only beginning their battle over the Supreme Court vacancy, with a smattering of television ads and behind-the-scenes research serving as warning shots in what's sure to be an expensive fight that will color November's elections.

Activity will only ramp up once President Barack Obama names someone to replace the late Justice Antonin Scalia ? a nomination Senate Majority Leader Mitch McConnell, R-Ky., and other Republicans promise the chamber will never consider. Many expect Obama to announce his pick next week.

With the court's 4-4 balance between liberal and conservative justices in play, both parties and their allies are reaching out to rally their memberships, solicit contributions and savage the opposition.

The conservative Judicial Crisis Network has run TV spots backing GOP senators in seven states and digital ads targeting Democrats in four others, while its leader wrote an article criticizing one potential nominee for a case she handled as a public defender a decade ago. On its website, the legislative arm of the National Rifle Association links readers to an article titled "Justice Barack Obama?" suggesting that scenario should Democrat Hillary Clinton become president.

The Senate Majority PAC, backing Democrats, has launched a New Hampshire TV ad accusing GOP Sen. Kelly Ayotte, in a competitive re-election race, of "ignoring the Constitution, not doing her job." And Citizens United, dedicated to overturning the Supreme Court decision that unleashed unlimited campaign spending by corporations and unions, has aired commercials pressing Ayotte and Sen. Roy Blunt, R-Mo., to consider a nominee. A group of 21 Democratic attorneys general penned a letter warning Senate leaders not to "undermine the rule of law." MoveOn.org and other progressive groups plan rallies outside senators' home-state offices on a March 21 "National Day of Action."

"A Supreme Court nomination is the No. 1 top priority for almost any conservative group," said Carrie Severino, the Crisis Network's policy director, a sentiment shared by liberals, too. "Almost every issue ultimately finds its way to the Supreme Court."

Democrats and liberals have focused on Senate Judiciary Committee Chairman Charles Grassley, R-Iowa, and other Republican senators seeking re-election this fall in swing states like Ohio, Pennsylvania and Wisconsin. Backed by nearly all GOP senators, Grassley has said his panel won't hold a hearing on Obama's choice.

Justice Clarence Thomas stunned lawyers, reporters and others at the Supreme Court on Monday when he posed questions during an oral argument for the first time in 10 years.

It was the second week the court has heard arguments since the death of Justice Antonin Scalia, Thomas' friend and fellow conservative. Thomas for years sat directly to Scalia's right. Scalia's chair is now draped in black in a tribute to his death on Feb. 13.

Thomas' questions came in case in which the court is considering placing new limits on the reach of a federal law that bans people convicted of domestic violence from owning guns.

With about 10 minutes left in the hourlong session, Justice Department lawyer Ilana Eisenstein was about to sit down after answering a barrage of questions from other justices. Thomas then caught her by surprise, asking whether the violation of any other law "suspends a constitutional right."

Thomas's unusual silence over the years has become a curiosity over the years. Thomas has previously said he relies on the written briefs and doesn't need to ask questions of the lawyers appearing in court.

Thomas last asked a question in court on Feb. 22, 2006. He has come under criticism for his silence from some who say he is neglecting his duties as a justice. The 10-year milestone of his courtroom silence came just days after Scalia's death. Thomas was one of only two people invited by Scalia's family to recite a prayer during the funeral Mass on Feb. 20.

The Supreme Court is refusing to disturb a ruling from New Jersey's top court that sided with Gov. Chris Christie in a legal fight with public worker unions over pension funds.

The justices did not comment Monday in rejecting the unions' appeal. The high court order came less than three weeks after Christie ended his run for the Republican presidential nomination.

New Jersey's Supreme Court ruled last year that the state is obligated to pay individual retirees their pensions. But it overturned a lower court ruling that would have forced the state to come up with billions to pay promised pension benefits.

Watching the fight unfold between President Barack Obama and Senate Republicans over who should choose the next Supreme Court justice, Michael A. Bowden got angry at what he saw at the latest affront to the first black president.

And then his thoughts turned from Washington to his own state.

Obama won't be on the ballot this fall, but Pennsylvania GOP Sen. Pat Toomey will ? and Bowden has made defeating him in November a priority.

"This kind of thing really burns me to the core," said Bowden, a 56-year-old Air Force veteran from Philadelphia. "I've already started planting the seed in people's heads that Sen. Toomey is one of those people in lockstep with the Republicans. This could give him a wake-up call that he could be vulnerable as well."

Democrats are pressuring senators in Pennsylvania, Ohio, New Hampshire, Illinois and Wisconsin to back down from their refusal to confirm or even consider Obama's nominee to succeed the late Antonin Scalia or face the consequences in November.