The 2004 presidential election was marked by controversy with allegations of electoral fraud in the conduct of the second round runoff ballot between opposition candidate Viktor Yushchenko and the government-backed candidate and former Prime Minister Viktor Yanukovych. After mass nationwide protests, colloquially known as the "Orange Revolution," a new election was held on 26 December 2004 in which Victor Yushchenko was declared the winner with 52% of the vote and was subsequently sworn into office on 23 January 2005. Victor Yanukovych again served as Prime Minister.