In this week's UpFront, we speak to former Mexican President Vicente Fox who has compared Trump to Hitler. In the Reality Check, Mehdi Hasan looks at the likelihood of the Republican frontrunner becoming US president. And in the Arena we speak to Iranian writer Azar Nafisi and Iranian-American journalist Negar Mortazavi about the impact of this week's elections in Iran. This week, Donald Trump moved closer to obtaining the US Republican presidential nomination after winning seven of the 11 states up for grabs during the Super Tuesday elections. Trump has promised to build a wall to keep Mexican immigrants out of the US, drawing sharp criticism on both sides of the border, including from former Mexican President Vicente Fox. Fox compared Trump to Hitler and strongly denounced the billionaire businessman's plan to build a wall. In this week's Headliner, Fox says Trump is "absolutely" racist and his "discriminatory speech is creating violence within the same United States". Reality Check: The truth about the Trump phenomenon After Donald Trump's Super Tuesday gains, the billionaire businessman is likely to become the US Republican presidential nominee. But does Trump really have the public support that will get him all the way to the White House? In this week's Reality Check, Mehdi Hasan highlights why the Republican frontrunner may not become the next president. Iran elections: Change or no change? Iranian President Hassan Rouhani celebrated this week after an unprecedented victory for reformist candidates in Iran's elections - the first since the nuclear deal was made. Rouhani said the election results "open a new chapter" for the Islamic Republic, but critics argue they distract attention from the country's ongoing economic problems and human rights abuses. In this week's Arena, we discuss the impact of the results on Iran's political landscape with Iranian writer and dissident Azar Nafisi and Iranian-American journalist Negar Mortazavi. Nafisi asserts