WASHINGTON -- Former Republican Sen. Norm Coleman threw support behind Jeb Bush's presidential bid Monday.

Coleman, a former one-term Minnesota senator, was previously supporting Sen. Lindsey Graham's presidential bid and running his super PAC. Graham ended his bid in December and in January said he was supporting Bush, a former Florida governor sagging in the national polls.

On Fox News on Monday, Coleman followed his lead. He said, from an apparently sunny locale, that Bush is the one person "ready to be commander-in-chief on day one, the one person that put together in November, before Paris, before San Bernardino, a plan to defeat ISIS, is Jeb Bush," he said, referring to the terrorist group the Islamic State.

"That's the issue," Coleman said. "National security is the issue."