You could look it up, part 2a

 After the death of Rush Limbaugh, Ross Douthat had a piece in which he said "The United States has moved dramatically leftward since the 1990s, on social issues especially but economic ones as well."  He's right about social issues, although the shift goes back farther than the 1990s.  For economic issues, he cites a survey question asked by various survey organizations about whether you'd prefer a bigger government providing more services or a smaller one providing fewer.  I reproduce the figure showing changes (from the Pew Research Center):

So opinion has moved left since the 1990s, but over the whole period, there is no trend.  Looking at the whole series, it looks like the 1990s were an unusually conservative time--apart from that, there hasn't been much variation.  This is similar to the pattern in several questions from the GSS, although the conservative movement in the 1990s is not as pronounced there.   Then there is the question about the government providing a job and good standard of living from the ANES that I wrote about recently.  The 1990s don't stand out in that one, but it's less useful for looking at short and medium term variation since it's taken only once every four years.  All of them agree in showing little or no trend since the 1970s.  So rather than a general liberal trend, I think there has been a liberal movement on many social issues but no real trend on economic issues.