Liberals feel entitled to rule. They are "on the right side of history." Liberals are driven by the "fierce urgency of now." This is the modern-day equivalent of the divine right of kings, without the divine participation. Liberals are absolutely certain that their government experts know how to take care of people better than people can take care of themselves. Liberals think this is so obvious that they can't believe anybody can have any doubts about it. So any opposition is preventing liberal government experts from providing people with superior services. These opponents must have self-serving, evil motives because it is so obvious to liberals that the government experts do a superior job. Liberals' faith in government's ability to solve any and every problem is fanatical in their voter base. Any evidence that government has failed just means that the government didn't spend enough money on the problem. Evidence of fraud, corruption or incompetence is discounted because liberals are metaphysically certain that the fraud, corruption and incompetence would be much worse in the private sector. Even though the same individuals work in the private sector and public sector, moving back and forth through the famous revolving door, the liberal equivalent of transubstantiation consecrates these individuals while they work for the government.
As you can see, liberals go almost immediately to ad hominem attacks because they can see no rational reason anyone would oppose them. They also believe government is the best solution, so obstacles like the law or the Constitution are unimportant compared to the "fierce urgency of now." If the law gets broken or the Constitution gets rewritten by a 5 to 4 "living Constitution" decision in the Supreme Court, it's OK because it puts us "on the right side of history." For liberals, the ends completely justify the means.