Forget the polls. Forget the pundits (present company excepted, of course). Democrats cannot lose peacetime national popular elections ever again. There are several reasons for this, but there is one overriding reality that drives all the others: Democrats are the party of Government, and government is now a clear majority of the U.S..
Average government spending amounted to about 65% of the private sector GDP during Obama's term. Nothing close has ever occurred during peacetime in the U.S..
65% is an insurmountable majority for Democrats in popular votes. Sorry. That's just how it works in a democratic republic.
A picture is worth a thousand words:
(All numbers are from usgovernmentspending.com. Note: most of Obamacare is not included in any measure of government spending. Although it is a massive new government program, the majority of the spending flows from citizen, to Insurance Co., and then back to other citizens, never touching government books. Obamacare is an "off the books" entitlement.)