Why didn't the Democrats run more aggressively on the economy this year?

[Mehmentum]

Because while the economy is growing, the lower and middle classes aren't feeling it.  Most of the growth is happening to the already very wealthy.

Wages are stagnant and most of the new jobs are poor, low paying ones.  Saying that the economy's doing well would be pretty insensitive.

Now, that's not to say there isn't an argument to be made for Democrat's handling of the economy.  Its just a more nuanced argument.  'Look at how Europe and Japan are doing.  Both are looking at another recession.  The U.S. is doing well in comparison. etc.'  And nuanced doesn't exactly work well in politics.