Rubio’s pendulum swing may or may not ultimately appease those angry about the pivotal help he provided to win passage of the Senate’s comprehensive immigration bill, with its path to citizenship for most undocumented immigrants. What’s already certain is that some establishment figures who applauded him on immigration, including Sens. John McCain of Arizona and Lindsey Graham of South Carolina, are now serving up disapproval. Other Republican critics of the shutdown threat include Sens. Tom Coburn of Oklahoma and Richard Burr of North Carolina, as well as 2012 nominee Mitt Romney.

Business lobbyists are also dismissive, with several telling National Journal that Rubio & Co. are ignoring facts on the ground—to wit, a Democratic president and Senate. Conservative columnist Charles Krauthammer called the defunding effort “nuts.” Commentary writer Peter Wehner, a White House aide during the Reagan, Bush I, and Bush II administrations, got personal with a column headlined “Marco Rubio’s Folly.”

What’s more, Rubio may be sowing confusion about his political identity as he heads toward a widely expected run for president in 2016. Would he be an establishment contender, along the lines of a Chris Christie, Scott Walker, or Jeb Bush, or an insurgent like Paul or Cruz? “It appears right now as if the path is not clear for Rubio. And sometimes if one foot is in each camp, neither camp adopts you as their own,” says University of New Hampshire political scientist Dante Scala, an expert on the state’s first-in-the-nation primary.