US Republican presidential candidate Ted Cruz speaks during a campaign event in Ida Grove, Iowa January 30, 2016.[Photo/Agencies]

A darling to the conservative Tea party, Cruz won his election to the US Senate in 2012. Since his arrival in Washington, D.C., Cruz has been a vocal critic of both US President Barack Obama as well as Republican leaders.

While attacking Obama on almost all issues had become a routine for Republicans in the past seven years, Cruz stands out for his equally harsh criticism against GOP leaders for what he calls their willingness to compromise when dealing with the Obama administration.

He became a national political figure in October 2013, when his opposition to Obama's 2010 healthcare law led to a partial government shutdown.