Ukraine crisis: How does Obama handle uprisings?
President Barack Obama has seen more revolutions and uprisings on his watch than many other recent US leaders.
And like the Arab Spring and Iran's Green Movement protests, the situation in Ukraine has proved difficult for the American president to navigate.
In some cases, such as during the 2009 protests in Iran, Mr Obama has been criticised for not doing enough as violence grew.
Yet two years later he helped lead a widely supported military intervention during Libya's civil war.
All the while Mr Obama must keep a close eye on US public opinion, which is wary of American military involvement in foreign affairs after the wars in Iraq and Afghanistan.
The BBC's David Botti takes a look back.
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