Christie, Walker and Jindal have all adopted conservative policies this year.
O'Malley "continues the strange and disastrous agenda of Barack Obama," Palin wrote.
Hillary Clinton’s presidential campaign scored a major outreach victory late last week.
Fiorina called Hillary a political elite who does not deserve the Oval Office.
"The presidency is not a crown to be passed back and forth by you between two royal families."
Mark Hensch 05/29/15 10:18 AM EDT
O'Malley plays "Hail to the Chief" in a video clip.
Democrats interviewed by The Hill insist Martin O’Malley has a chance.
Devin Henry 05/28/15 05:02 PM EDT
Candidates are faced with difficult calculus as they prepare their early state strategies.
Christie said the education standards have brought "confusion and frustration"