Obama vows to avoid activist Supreme court pick

US President Barack Obama on Wednesday set out his criteria for picking the next Supreme Court justice, insisting he will not tap someone looking to legislate from the bench.

Obama's bid to nominate a successor to conservative justice Antonin Scalia, who died unexpectedly this month, has ran into the sand in Congress, where Republicans have already vowed to block his nominee.

Vowing to consult "people across the political spectrum" in making his choice, Obama said he would pick someone "who recognizes the limits of the judiciary's role; who understands that a judge's job is to interpret the law, not make the law."

"I seek judges who approach decisions without any particular ideology or agenda, but rather a commitment to impartial justice, a respect for precedent, and a determination to faithfully apply the law to the facts at hand," he wrote on the SCOTUSblog website.

The nominee must also see that "justice is not about abstract legal theory" but has an impact on Americans' lives.

Obama has already appointed two Supreme Court justices, Elena Kagan and Sonia Sotomayor, who are both seen as liberal.

His comments are likely to be seen as a hint that he may pick a centrist to replace Scalia.

Obama repeated his demand that the Senate do its job.

"The Constitution vests in the president the power to appoint judges to the Supreme Court. It's a duty that I take seriously, and one that I will fulfill in the weeks ahead," he said.

"As Senators prepare to fulfill their constitutional responsibility to consider the person I appoint, I hope they'll move quickly to debate and then confirm this nominee so that the Court can continue to serve the American people at full strength."