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.
