By Lawrence Hurley

WASHINGTON (Reuters) - Most Americans would support imposing a term limit on the nine U.S. Supreme Court justices, who now serve for life, a Reuters/Ipsos opinion poll has found in the aftermath of major rulings by the court on Obamacare and gay marriage.

Limiting terms would be difficult, requiring an amendment to the U.S. Constitution. Congress shows no signs of taking up the idea, though Republican presidential contender Ted Cruz has suggested the possibility of justices being voted out of office.

Support for the 10-year term limit proposed by the poll was bipartisan, with 66 percent saying they favored such a change while 17 percent supported life tenure.

The two big rulings in June were widely welcomed by liberals. Nevertheless, 66 percent of Democrats, 74 percent of Republicans and 68 percent of independents said they favored the 10-year term limit idea, according to the poll.

Respondents were not asked their preference on how long the justices' terms should last. Over the years, legal experts have debated 8-, 10-, 14- and 18-year limits.

The poll showed broad understanding of the court, with 68 percent saying they knew justices are appointed, not elected, and 60 percent saying they knew the appointments are for life.

Under the Constitution, presidents appoint the justices subject to confirmation by the U.S. Senate, a process only 32 percent of respondents backed. Forty-eight percent said justices should be elected.

There was little support in the poll for tinkering with the court's role as the final arbiter of U.S. law. Only 29 percent said they would support allowing Congress or the president to overrule court decisions.





HIGH COURT CLOUT

The poll was conducted after the court in June legalized same-sex marriage nationwide and rejected a conservative group's challenge to Democratic President Barack Obama's healthcare law, drawing renewed attention to the high court's clout.

The court can decide what rights Americans have, and it can strike down laws passed by Congress if they are deemed to violate the Constitution.

Since its founding in 1789, the court has tackled the country's most divisive issues, ranging from property rights and slavery to racial segregation and abortion. Both the same-sex marriage and Obamacare rulings, decided by majorities of 5-4 and 6-3 respectively, were highly unpopular among Republicans. The party's 2016 presidential hopefuls roundly condemned them.

After the rulings, Cruz said the court had "crossed from the realm of activism into the arena of oligarchy." He said justices should face periodic retention elections, as many U.S. states require for their state-level high courts.

More than 80 percent of respondents who said they identified strongly with the conservative Tea Party movement said they would favor the 10-year term limit.

A nonpartisan advocacy group called Fix the Court wants justices to voluntarily step down after 18 years. Chief Justice John Roberts marks a decade in office in September. Of his eight colleagues, five have served for more than 20 years while the other three were appointed in the last decade.

"It's not surprising that Supreme Court terms limits are supported across party lines since, as a nation, we've always felt it's wrong for a handful of individuals to hold on to immense power for decades on end, as is the current trend at the high court," said Gabe Roth, Fix the Court's executive director.

Of the nine justices, five were appointed by Republican presidents and four by Democrats. The longest serving sitting justice is Antonin Scalia, appointed by President Ronald Reagan in 1986.

To take effect, a constitutional amendment must go through an adoption and ratification process requiring overwhelming support of Congress and the states. The last amendment ratified was the 27th in 1992. It prevents members of Congress from giving themselves pay raises during current sessions.

The poll was conducted between July 10 and July 17 among 1,611 people. Reuters/Ipsos online polls are measured with a credibility interval. Among all respondents, the Supreme Court poll had an overall credibility interval of plus or minus 2.8 percentage points.





Click here for graphics - http://graphics.thomsonreuters.com/15/07/USA-COURT-POLL.jpg





(Reporting by Lawrence Hurley; Editing by Kevin Drawbaugh and Howard Goller)