The former Maryland governor says both Sanders and Clinton are vulnerable on immigration.
The Florida Senator has received 15 of his 19 lawmaker supporters in the last two months.
"You look at our border — it is completely porous," said the 2016 hopeful.
New Jersey Gov. Chris Christie took several potshots at Sen. Ted Cruz (R-Texas) on Tuesday, suggesting his GOP presidential rival is weak on national security.
Hillary Clinton says she would like to see Russia involved as much as possible.
Trump said he would give the amount to wounded soldiers or veterans.
Cruz is linking his 2016 presidential rival to Hillary Clinton on Libya.
"Yes, anyone who wants contraceptives can access them," he said.
James Comey is the pivotal figure in the 2016 race that no one is talking about.
GOP activists in Iowa believe Cruz could now be the best-positioned candidate.