The Republican plans to start his White House campaign on June 6, Santorum announced Thursday on his Facebook page. He then would head to Iowa and New Hampshire.
Santorum already had announced his presidential ambitions and he has been aggressively campaigning in the early nominating states of Iowa, New Hampshire and South Carolina. He also has hired veterans of past presidential runs.
Santorum, who lost a bruising re-election bid in 2006, has spent the time since leaving office working at a think tank and speaking to conservative groups.