Rasmussen is a fake poll and has been ever since it changes hands. Anyone pollster can produce a ten point lead if they push one candidate under 40% (highly unrealistic). The fact that they can only get Trump to 46% speaks volumes. 46% is his base.
I think Biden had a bump in Feb/Mar and now it's faded and we're approximately back where it was around the New Year, with polls split between nearly tied and a Republican version of 2008. However, even the nearly tied scenario suggests Trump would be favored in the EC.
Rasmussen has consistently posted off the wall numbers and written biased commentary to accompany their polls. They are literally they only pollster with Trump leading by 10% and it's obvious from the numbers what sort of games they pulled to get them. Their last poll was something like 52-47 Trump now they've switched to this.
