Polling using the word “liberal” is pretty pointless. Leftists and centrists have completely different opposing definitions of what it means, and most Americans don’t have a clue.
That would seem much more to point towards polling using the word 'liberal' being more useful than trying to apply leftist definitions, since most Americans don't have a clue about the distinction.
Polling on specific issues or particular politicians is the only way to get an accurate picture, and Americans, especially Democrats, are far more left than they self identity.
Funny that polling on specific issues and particular politicians rarely if ever translates into actual voting patterns, even in ballot initiatives. Almost like "Do you like GOOD THING?" gets positive responses until someone points out, rightly or wrongly, that there are other effects, like universal healthcare requiring minor tax rises.
Likewise, having a positive view of a politician is not the same as voting for them, or Bernie wouldn't have lost two fucking primaries due to the more left-leaning of the two parties rejecting him by double-digit percentages in favor of neoliberal ghouls.
"THE COUNTRY IS SECRETLY LEFT-WING" is just as blinkered and fucking idiotic as "THE SILENT MAJORITY IS WITH US" from the GOP.