What makes the dark horses run?

The potential 2016 presidential field is a long list full of long shots.

Former New York Gov. George Pataki (R), has said he is “very seriously" considering a bid.

Socialist Sen. Bernie Sanders (I-Vt.) appears to be mulling a challenge to frontrunner Hillary Clinton for the Democratic nomination.

Former Sen. Jim Webb (D-Va.) is an all-but-declared candidate yet acknowledged in an onlinevideo that he would need to “overcome what many commentators see as nearly impossible odds.”

Do such unfancied candidates really believe they can win? Often, the answer — rooted in hope, optimism and the understanding that the Beltway conventional wisdom can be spectacularly wrong — is yes.

“The presidential primaries are just like the NCAA [basketball] bracket,” said Boston University professor Tobe Berkovitz, who specializes in political communications.

More