The state of Virginia will no longer defend its ban on same-sex marriage. Newly elected Attorney General Mark Herring, a Democrat, announced the decision today. He said he believes the ban is unconstitutional.

　　ATTORNEY GENERAL MARK HERRING, Virginia: The United States Constitution is the law of the land. So a state law and a state constitution cannot violate the United States Constitution. And I swore a duty to uphold both. And the Supreme Court is clear. The United States Constitution is the law of the land, supreme law of the land.

　　GWEN IFILL: Last year, the Supreme Court struck down the Defense of Marriage Act and allowed gay marriages to resume in California.

　　A United Nations envoy struggled to hold the Syrian peace talks together today. The Assad regime and the Western-backed opposition traded barbs at a distance, without saying if they will sit down for direct talks. We will get a full report on the day's developments later in the program.

　　Iran's President Hassan Rouhani is promising to adopt policies of prudence and moderation, including a final nuclear deal. He told the World Economic Forum in Davos, Switzerland, that his government wants constructive engagement with the global community. And he insisted any nuclear efforts will be for peaceful purposes only.

　　PRESIDENT HASSAN ROUHANI,Iran (through translator): The Islamic Republic of Iran has a strong will, a serious will. Again, when it comes to the nuclear program, to reach a comprehensive agreement, I do not foresee an impediment. Iran has never pursued a nuclear weapon, and it will never desire to have one in the future.

　　GWEN IFILL: Rouhani also met with Western and Arab businessmen, telling them Iran wants new investments in its economy.

　　In Ukraine, protesters stormed government offices in three cities today, but a tense standoff held in Kiev as the president met with opposition leaders who oppose closer ties with Russia.

　　Matt Frei of independent television news is in Kiev.

　　MATT FREI:Old tires are the new currency of the struggle, essential for creating the wall of fire that renders the other side blind, especially when the wind is on the side of the revolution.

　　What we see here right on the front line is a battle between the elements. The protesters are using smoke and fire, and the police are using water.

　　Just as things looked as if they were getting even more out of hand, a visitor arrived at the barricades, the tallest and certainly most famous Ukrainian on hand, Vitali Klitschko, heavyweight world champion, politician, and fast emerging as the most popular opposition leader.

　　"I have taken responsibility," he told the crowd. "There will be a truce until 8:00 this evening, while we resume talks with the government."

　　The talks this afternoon may have produced a compromise of sorts, but no one is taken anything for granted. The supply lines of tries continues to make its way to the barricades.

　　GWEN IFILL:Negotiators for South Sudan's government signed a cease-fire with rebel forces today in Ethiopia. The fighting has killed thousands of people and driven thousands more from their homes since mid-December.

　　And a transitional president took office today in the neighboring Central African Republic. Catherine Samba-Panza was sworn in as the nation's first female leader. She's asked for the Muslim fighters behind last year's coup and Christian militiamen who've fought them to support peace.