People who identify as a Republican or a Democrat fluctuates between 27-33% with an mean of 30%. Independents are 40%.

If the poll adds +10% Democrat and under samples Independents by 17%. It is way off from the actual voter base and useless.

During the impeachment charade. A poll of people who wanted Trump impeached was at 55% and 46% of those polled were Democrat...

These pollsters just skew who they poll to get the result they want.