Speaking in Belfast, US Secretary of State Hillary Clinton says violence is "never an acceptable response" to political disagreement. But is she using her visit to launch a bid for the White House?

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US Secretary of State Hillary Clinton used her visit to urge an end to the new outbreak of violence in Northern Ireland. She said: "It is never an acceptable response to disagreements."

She was speaking at a press conference which was also attended by First Minister Peter Robinson and Deputy First Minister Martin McGuinness.

Earlier, a death threat was issued against East Belfast MP Naomi Long, who was warned by police to stay away from her home and constituency office, where loyalists staged demonstrations in protest against a decision by the city council to limit the flying of the union flag.

Vital role

Secretary Clinton first visited Northern Ireland with her husband, the former US president Bill Clinton, during the 1990s. President Clinton visited Belfast three times, having become the first serving first US president to visit the region in 1995.

President Clinton played a vital role in getting both sides to agree to ending violence in Northern Ireland, one of the biggest foreign policy triumphs of his administration.

He famously shook Gerry Adams's hand on the Falls Road in 1995, an event which now features in the official Belfast bus tour. In 1995 Hillary joined her husband to turn on the Christmas lights in Belfast, an iconic moment just a year after the first IRA ceasefire - and one which she referred to at the start of her press conference on 7 December.

The appointment of George Mitchell to broker a political settlement is seen as the most important foreign policy decision of the Clinton administration, one which created lasting legacy for the president as a peacemaker.

If the secretary of state hopes to run for president in 2016, associating herself with the success of the peace process and highlighting her experience in global affairs will strengthen her bid.

During her first official visit as secretary of state in 2009, she urged the devolution of policing and justice powers from London to Belfast. This visit will be one of her last foreign engagements as secretary of state before she steps down next month.

Hillary's legacy

Secretary Clinton has been busy across the globe since she took up the role in 2008, helping to secure the release of Chinese dissidents and putting pressure on India over trade with Iran.

She has set a record in her role as the best travelled secretary of state. In four years she has visited over 100 countries, taking in everywhere from Afghanistan to Zambia - and even new states such as Timor-Leste and South Sudan. In the process, according to official records, she has clocked up close to 1 million miles.

During talks at an international summit in Dublin yesterday, Secretary Clinton continued to take a strong line on Syria, meeting with Lakhdar Brahimi, the UN envoy to Syria, and Russian Foreign Minister Sergei Lavrov.

She warned that pressure against the regime in and around Damascus was increasing and raised fears over Syrian chemical weapons.

Mrs Clinton said: "I think we will discuss that and many aspects of what needs to be done in order to end the violence and begin that transition."

She echoed President Barack Obama's warning that any action involving these weapons would cross a "red line" and provoke action, but did not specify what kind.

Clinton in 2016?

In the United States, many believe Secretary Clinton should become a presidential candidate in 2016. 57 per cent said they would back her candidacy in a recent poll by the Washington Post, while 82 per cent of Democrats are behind her.

The editor of the New Yorker magazine has predicted Hillary will run in 2016, and many believe she is stepping down from her current role to prepare for her next move.

At a recent conference on Israel, a video with endorsements from a number of international leaders including Tony Blair and Jordan's defence minister, Nasser Judeh, was played.

The video concluded with Israeli Prime Minister Binyamin Netanyahu declaring: "As someone who knows a thing or two about political comebacks, I can tell you I don't think we've heard the last of Hillary Clinton."

However, she continues to deny that she plans to run for president in 2016. Commentators have claimed her 2008 nomination bid was soured by announcing her candidacy too early.

New York mayor Michael Bloomberg has urged Secretary Clinton to instead consider running for his job when he steps down next year.