What do you consider liberalism? The modern definition of liberalism kept the concept of social liberalism (at least to a degree) and, in that sense, people are certainly become more liberal. On the other hand, liberalism, in the classic sense, pertains to all types of liberalism - not just including social issues.
You can see that liberalism is on the rise in many aspects of society. It is most obvious when watching TV these days, specifically entertainment news. Society is more accepting of human behaviors that just a few decades ago were considered to be deviant. America has strayed from its conservative roots.
Mainstream Republicans howled against the George W. Bush administration's handling of two unpopular wars. When the 2008 Presidential Election came around, Sen. John McCain was too much of a Bush supporter and a warmonger to be taken seriously by independent voters. Liberalism is on the rise in that Republicans can't seem to grasp the multicultural makeup of the most important voting blocs in the United States. The GOP is the party of old white men, not young Hispanics or blacks who make up a large section of the voting population.
Yes, I think that liberalism is on the rise in America, because people are not shy about being socialist anymore. McCarthyism used to be something that was frowned upon, but any more, legislators can say that having to have a full-time job is an imposition, and we are just expected to all go along with that. Liberalism is on the rise.
Like it or not, Obamacare has become the downfall of this presidency. With the downfall of the leading liberal, conservatism is back on the rise. This could have been prevented with the electronic roll out. Unfortunately, that was a great failure on so many levels. While the blame should not be on the liberal left alone, it mostly is. The conservative right was spiraling fast after a failed sequester, and this is the only thing that saved them. Had Obamacare been implemented smoothly, Liberalism would be moving hard and fast towards another four years in the Casa Blanca.