Great chart above from Michael Tesler highlighting the opinion dynamics of the budget deficit. When George W. Bush was president, better-informed Democrats "knew" that the deficit was a huge deal, while better-informed Republicans "knew" it was overblown. With Barack Obama in office, the posiitions flip.
And it's crucial to understand that the flip-flopping happens with the best-informed people, not the worst-informed people. If you're well-informed, you gain a lot of information about "your side's argument" on the issues of the day and map your opinions to the shifting political currents. I remember that back in the mid-Bush years I worked at a magazine whose founders were die-hard deficit doves who were extremely annoyed with the deficit scold strain of thinking in Democratic Party circles, and it was always very difficult to frame the argument "yes the Bush administration's fiscal policies are bad, but no it's not because deficits are out of control" in a way that was compelling to the audience.