The poll found against Walker, Clinton leads 48 percent to 44 percent. By comparison, former Florida Gov. Jeb Bush (R), who like Walker and Clinton, has shown strong interest in running for president, trails the former secretary of state 49 percent to 41 percent, a shift from December when Clinton led Bush 53 percent to 40 percent.
Against Sen. Marco Rubio (R-FL), Clinton leads 49 percent to 42 percent. She fares better against Sen. Rand Paul (R-KY), 51 percent to 40 percent, just slightly down from December when she led the Kentucky senator 54 percent to 40 percent.
Clinton's best matchup seems to be against Sen. Ted Cruz (R-TX). The new poll found Clinton leading Cruz 53 percent to 39 percent, only slightly changed from December when she led Cruz 54 percent to 39 percent.
The fact that Clinton is polling below 50 percent against much of the likely 2016 Republican presidential field suggests some vulnerability, Marist Institute for Public Opinion director Lee Miringoff said.
"It gets us back to stuff people find unpleasant about the Clintons," Miringoff said.
The poll was conducted among 1,253 adults between March 1st and March 4th. The margin of error was plus or minus 2.8 percentage points.