Princeton historian Julian Zelizer believes that Democrats in Congress have the ability to make real trouble for Republicans so long as they stay unified and remain determined to gum up the works.In an interview with The New Republic’s Greg Sargent, Zelizer points out how invincible President George W. Bush appeared after he won reelection in 2004 and entered his second term with majorities in the House and Senate that were significantly larger than what Trump currently enjoys.In that case, then-Democratic leaders Nancy Pelosi and Harry Reid made sure their caucuses were lined up uniformly against Bush’s second-term priority of privatizing Social Security, which eventually crashed and burned as his approval rating sank under the twin disasters of Hurricane Katrina and the Iraq War.Were Democrats to take a similar approach now, argues Zelizer, they could potentially enjoy similar success.ALSO READ: Trump nominee’s ‘outrageous lie’ before Senate singled out by MSNBC host”Democrats not only have to be strong, but one of the things they can do is create very small fissures in the House Republican caucus, for example, and it will cause immense problems for the Republicans to be able to do anything,” he contends. “That is going to be a challenge for Trump and the GOP moving forward, and that’s exactly what Democrats, if they want to be successful, have to figure out how to exploit.”Above all that, he says, Democrats need to embrace acting as partisans rather than making noises about cooperating with Trump.”It’s what Democrats need to be thinking of, to really understand the value that partisanship can have when not done in the way Republicans have done it,” he emphasizes. “They have to deploy that power in the coming years.”