LOS ANGELES - The US state of Washington became the seventh in the nation to legalize same-sex marriage when Governor Christine Gregoire on Monday signed into law a bill approved last week by lawmakers.

"I'm proud our same-sex couples will no longer be treated as separate but equal," Gregoire said, as gay marriage supporters who gathered for the signing ceremony in the state capital Olympia applauded.

Six US states -- Connecticut, Iowa, Massachusetts, New Hampshire, New York and Vermont -- plus the District of Columbia already allow same-sex marriage.

The law will go into effect on June 7 in the northwestern US state unless opponents manage to gather enough signatures to hold a referendum on overturning the measure.

If opponents are successful, the law would be held in limbo until the results of the referendum, to be held on November 6 along with the presidential and congressional elections, are tabulated.

Same-sex marriage remains a highly controversial issue in the United States.

Lawmakers in the state of New Jersey, many of them Democrats, on Monday approved legislation legalizing same-sex marriage -- but Republican Governor Chris Christie has said he will veto the measure.

A group of 80 US mayors -- including New York's Michael Bloomberg, Chicago's Rahm Emanuel, Antonio Villaraigosa from Los Angeles and Annise Parker from Houston -- last month unveiled a campaign to win support for same sex marriage.

Gay marriage was briefly authorized in California in 2008, but later banned by a referendum re-writing the state's constitution to restrict marriage to unions between a man and a woman.

A US federal appeals court last week then declared the California ban on same-sex marriage unconstitutional.

Opponents are expected to appeal, and the legality of same-sex marriage will likely be decided by the US Supreme Court.

CHICAGO - The upcoming visit of Chinese Vice President Xi Jinping, the growing Asian power's likely next leader, is going to be the biggest thing that's happened to Iowa since Pope John Paul II visited in 1979, the farm state's governor said Monday.

"I'd say it ranks with the Pope's visit to Living History Farm and (Soviet premier Nikita) Khrushchev's visit here to Iowa in 1959," Governor Terry Branstad told reporters.

The Pope's visit drew 350,000 people while Khrushchev's tour of a farm in Coon Rapids, helped humanize the superpowers at the height of the Cold War.

"This one I think for the economic future of our state is even more significant," Branstad said.

Iowa's exports to China have soared in recent years as the Asian power's rising middle class buys more pork, corn, soybeans and other agricultural products from the US Midwest.

Branstad hopes to draw even more business thanks to the state's "personal relationship" with Xi, who spent several days there when he was a low-ranking local official on an exchange.

The long-time Iowa governor returned the visit last year, and was amazed to hear that Xi had kept the itinerary from the 1985 trip and spoke fondly of his hosts and the people he'd met there.

Xi will be reunited with his former hosts in Musatine, Iowa on February 15 before heading to Des Moines for a state dinner.

Xi meets with President Barack Obama on February 14 and is expected to deliver a speech in Washington before heading to Iowa. He is also expected to visit Los Angeles on February 16 and 17.

by Michael Thurston

LAS VEGAS - Republican frontrunner Mitt Romney holds a huge lead two days before Nevada's caucuses, a poll showed Thursday, as he looked to build on a Florida win to lock up his party's nomination.

The new survey came as Romney and his rival Newt Gingrich campaigned head-to-head in Las Vegas, where real estate mogul Donald Trump was set to endorse one of them -- Romney, according to the latest reports -- during the day.

Romney was back on track a day after stumbling with a gaffe about poor Americans, as a new poll gave him 45 percent to Gingrich's 25 percent of likely Republican caucus-goers.

Nevada Republicans hold caucuses on Saturday to pick 28 delegates to the Republican national convention, the first nominating contest in the western United States.

Trailing in the Nevada poll, by the Las Vegas Review-Journal and 8NewsNow, were former senator Rick Santorum with 11 percent and Texas congressman Ron Paul with nine percent.

Both frontrunner candidates headed from Florida to the western battleground state of Nevada on Wednesday, a day after Romney soundly defeated Gingrich in the Sunshine State, retaking the lead in the White House nomination race.

But the multi-millionaire former Massachusetts governor triggered immediate criticism for a controversial comment about America's poorest citizens, which threatened to slow his momentum.

"I'm not concerned about the very poor. We have a safety net there. If it needs repair, I'll fix it," said Romney, a wealthy businessman who last week acknowledged earning $20 million in 2010.

The remarks came as the race for the right to take on Democratic President Barack Obama in November widens into more states, and were quickly seized upon by his opponents.

But Romney swiftly tried to explain his remarks, telling reporters traveling with him on his plane that they should consider everything he said, rather than just part of a sentence.

"Of course I'm concerned about all Americans... poor, wealthy, middle class, but the focus of my effort will be on middle income families who I think have been most hurt by the Obama economy," he said later.

At a campaign stop in Las Vegas on Wednesday evening Romney was back on track, drawing cheers with his usual stump speech and taking digs at Obama's policies, including his backing for "European-style" health care.

Romney also attacked the "naivety" of an announcement Wednesday by Defense Secretary Leon Panetta that the US plans to end its combat mission in Afghanistan in 2013, one year before most US troops are due to withdraw.

"Why in the world do you go to the people that you're fighting with, and tell them the day you're pulling out your troops? It makes absolutely no sense," he told hundreds of supporters in a suburban Vegas warehouse.

On Thursday all eyes were on Trump, who scheduled a "major announcement" for 12:30 pm (2030 GMT).

Media including the New York Times initially cited sources Wednesday, including a senior Gingrich campaign official, as saying Trump would endorse the former House speaker.

But CNN and the New York Times both reported Thursday that Trump would endorse Romney.

Gingrich has been endorsed by ex-candidate Herman Cain, and former Alaska governor Sarah Palin had urged Florida voters to back him in order to extend the contest, a sign of his support among the ultra-conservative Tea Party.

However, most of the party's establishment figures -- including Senator John McCain and popular New Jersey Governor Chris Christie -- have backed Romney.

As the first western state in the 2012 Republican nomination battle, Nevada thrusts new demographics and issues into the limelight, including concerns over illegal immigration, the environment and natural resources.

Like Florida, the Silver State has been badly hit by the recession, with soaring unemployment and a housing market devastated by the 2008 meltdown.

Romney, who won handily here in the 2008 White House race, can expect a boost from fellow Mormons. Four years ago, 26 percent of Nevada Republican caucus voters were Mormon and 95 percent of them backed Romney.

NEW YORK - Hollywood star and weather seer Punxsutawney Phil used to be the only groundhog that mattered in weather predicting, but Phil's shock decision Thursday that spring is still six weeks away put him out on a limb.

As the eastern United States enjoys an exceptionally mild winter, most would have guessed that spring is around the corner. But when Punxsutawney Phil emerged from his burrow Thursday, his handlers announced he was able to see his shadow. According to tradition, that signals six more weeks of winter.

Nothing if not self-assured, the clever groundhog, whose persona starred in a Bill Murray comedy "Groundhog Day," immediately updated his Facebook page: "6 MORE WEEKS OF WINTER!!!!!!"

The ritual in Punxsutawney, Pennsylvania risked provoking skeptics, whether children looking forlornly at their unused sleds, or adults sweltering on their way to the office in winter overcoats.

As it happens, last year, in the thick of a particularly savage, snowy winter, Phil perkily suggested that he hadn't seen his shadow and therefore relief was around the corner. Maybe not so clever.

Americans might start paying more attention to Phil's often overlooked competitor Charles G. Hogg, the resident groundhog at Staten Island Zoo in New York City.

On being dragged out of his burrow Thursday in the presence of Mayor Michael Bloomberg, Chuck, as he's commonly known, did not see his shadow -- meaning, of course, that currently mild temperatures will stay that way right up until the official start of spring.

CBS reports that Chuck, who provoked admiration in some quarters when he bit Bloomberg's hand in 2009, has been more right than wrong since the Staten Island tradition started in the 1980s.

This year, even lesser rivals in Georgia and Ohio also reportedly failed to see their shadows, piling more pressure on poor old Punxsutawney Phil. It must be enough to make him want to slink back into hibernation.

In Washington, newcomer Potomac Phil -- a stuffed groundhog -- saw his shadow Thursday amid unseasonably balmy temperatures, in his inaugural prognostication at the bustling Dupont Circle roundabout.

"It looks like there are a lot of shadows out here folks. Six more weeks of winter and nine more months of gridlock in Congress," quipped city council member Jack Evans amid 150 spectators, WTOP all-news radio reported.

Groundhog Day, which falls each year on February 2, started with a German tradition in which farmers monitored the animal's behavior closely to make decisions about when their fields should be planted.

Punxsutawney held its first Groundhog Day in the 1800s, according to the official website.

MIAMI - White House hopeful Mitt Romney has opened up a commanding double-digit lead in Florida against main rival Newt Gingrich in their Republican nomination battle, the latest two polls showed Sunday.

Romney, a former Massachusetts governor and millionaire venture capitalist who is considered the party establishment's favored candidate, was routing former House speaker Gingrich by 15 points, 42 percent to 27 percent, just two days before the crucial Florida primary, according to an NBC/Marist poll.

The Miami Herald in its own poll published Sunday shows Romney ahead by 11 points.

Both surveys showed Christian conservative former senator Rick Santorum a distant third and libertarian-leaning congressman Ron Paul fourth.

Gingrich insisted on Fox News Sunday that the race for the large southeastern state would be "close," but the poll figures showed otherwise.

"What does Gingrich need to do? I would say Romney would need to implode," Brad Coker, the pollster who conducted the Miami Herald survey of 800 registered Florida voters, said in the newspaper.

"If there's no 11th-hour surprise... this race is looking right now like it's over."

Lee Miringoff, director of the Marist Institute for Public Opinion at Marist College, which conducted the NBC poll, also said Romney appeared headed for a decisive Florida victory.

"The bottom line in all this is Romney's sitting in the driver's seat going into Tuesday," Miringoff said on the MSNBC website.

Florida is the most populous swing state in the country and promises to be the scene of a major campaign showdown ahead of November's general election in which Republicans will seek to oust President Barack Obama, a Democrat.

The two polls were split on whether Obama or Romney would win in a November matchup.

NBC has Obama trouncing all Republicans, including Romney by 49-41 percent and Gingrich by a whopping 52-35 percent. But the Herald poll showed Romney beating Obama 48-44 in a theoretical general-election matchup, whereas Obama was seen winning handily in a face-off against Gingrich.

Both surveys have a margin of error of about 3.5 percentage points.