Hardtalk is in Phoenix, Arizona to meet the so-called toughest sheriff in America, Joe Arpaio.
His county, Maricopa, is near the border with Mexico where the issue of illegal immigration has turned into a national debate as the Arizona state government aims to bring in tough new anti-immigration laws.
Sheriff Arpaio has been conducting sweeps through largely Hispanic neighbourhoods to round up suspects for minor offences but also check on their immigrations status; a tactic which critics say is "racial profiling".
Stephen Sackur asks if Sheriff Arpaio undermining the US Constitution?
You can watch the full interview on Monday 23rd 2010 on BBC World News at 0330, 0830, 1530, 2030 GMT and on the BBC News Channel on Monday 23rd 2010 at 0230 and 0430 BST.