Proof?
Polls said Hillary would get more votes than Trump,she got millions more votes.The day before the 2018 mid terms polls had Trump at 42%,the next day he lost The House by the most votes ever and 23 of 33 Senate races by 18 million votes.Trumps first term average is 40 and The GOP is losing state and national races in Pennsylvania,Wisconsin,Michigan,Nevada,Virginia ,Minnesota , and Ohio and red states like Alabama,Louisiana,Kentucky,,West Virginia,Montana and Arizona.
What evidence do you have supporting polls are under reporting Trumps approval?