After weeks of focusing on a group of current and former elected officials in his search for a running mate, an unexpected surprise has come: Donald Trump is increasingly intrigued by the idea of tapping retired Lt. Gen. Michael T. Flynn in order to project strength and know-how on national security, according to four people familiar with the vetting process.Retired Lt. Gen. Michael Flynn. (DIA Public Affairs)

Flynn, 57, a registered Democrat but fierce critic of President Obama, previously ran the Defense Intelligence Agency.

The turn toward a military figure is being driven by Trump himself rather than by his advisers, the sources said, and comes as the real estate mogul is telling his friends national unrest may demand a “tough and steady” presence alongside him on the presidential ticket.

In Flynn, they added, Trump believes he would have a partner whom he can trust, based on their close working relationship over the course of the campaign on policy. And he likes the image of a businessman and a general coming to Washington as outsiders rather than an establishment elite.

The shift in how Trump is evaluating his short list is driven by his growing sense he does not necessarily want or need a running mate who will satisfy Republican insiders. Instead, Trump is more open than ever to going with a non-politician.