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.
In the April 2008 presidential election, he ran for the Colorado Party's nomination.  Initial results from the December 2007 primary showed Blanca Ovelar, backed by President Nicanor Duarte, winning over Castiglioni. However, this result was disputed and led to a recount.