He was a candidate for the Colorado Party's nomination in the April 2008 presidential election. Initial results in the December 2007 party primary election showed rival candidate Blanca Ovelar, who is backed by President Nicanor Duarte, narrowly defeating Castiglioni; however, the result was disputed, leading to a recount.
The candidate for the Colorado Party's presidential nomination in the April 2008 election was Castiglioni.  Initial results from the December 2007 primary showed a narrow victory for Blanca Ovelar, supported by President Nicanor Duarte, over Castiglioni. This result was disputed and led to a recount.