Castro launched his unexpected presidential campaign presenting himself as a political outsider and with a strong anti-establishment and anti-corruption speech. Promising to "rule by decree" and with a very loud "hard hand" rhetoric, Castro has been compared with figures like Donald Trump, Marine LePen and Rodrigo Duterte, and accused of right-wing populism and far-right positions, albeit he rejects the comparisons. Despite his unexpected lead in the polls throughout most of the campaign, his support plummeted in the final days. Castro came in fifth place, garnering only 9.56% of the votes in the February 4th Presidential Election. His poor performance did not qualify him for the runoff election scheduled for April 1, 2018.
Controversies
Antisemitism
In the July 30, 2019 editorial of the newspaper La Nación, Castro was accused of anti-Semitism for comments made in one of his official videos against the owner of the media CRHoy Leonel Baruch who is Jewish, making allusions and jokes about the Holocaust and also calling him an "evil banker." Castro's words were condemned by the Costa Rican Jewish community with an official statement from the Zionist Israelite Center. Castro's statements were also condemned by Israel's ambassador to Costa Rica Amir Ofek, who described them as "miserable expressions". The heads of most of the benches in the Legislative Assembly, including National Liberation, Citizen Action, Social Christian Unity, Broad Front and Castro's former party National Integration repudiated the expressions, the two Evangelical Christian parties' benches New Republic and National Restoration refused to comment, whilst the independent deputy Erick Rodríguez Steller, who is close to Castro, defended him arguing that his comments were taken out of context.
Conflict with reporters and the media
On November 24, journalist Arlene Raventós, who works in the Repretel network, showed that Castro's accusations against her that she was behind an alleged campaign to discredit him, were false. "It is unfortunate to have to go out to clarify false information without real content, published in the heat of a political campaign, which should be devoted to raising ideas about the real solution to the country's problems; but when it comes to muddying a name under and without foundation, the need to clarify with the truth prevails and that is what I request". On December 1, 2017, journalist David Delgado, who worked at La Nación and the Ministry of Justice and Peace, publicly denounced him for "persecution, mockery and harassment" in relation to coverage of a drug trafficking case. On December 11, 2017, he announced that he would sue the University of Costa Rica because a Facebook program of several young students reported the assault on his mother, his past as a politician and criticized what qualified his "right-wing populist" tendencies.
Castro was mentioned as part of the Panama Papers case by the news reports Amelia Rueda and Semanario Universidad for being lawyer for a Mossack Fonseca law firm related company, which led him to attack Rueda and her son Antonio Jiménez, as well as the media Semanario.