However, readily available information on the internet suggests you're wrong.
List of federal Legislative Branch politicians convicted of crimes while holding office, sorted by President.
Trump: 0 - Dems; 0 - Reps
Obama: 5 - D, 5 - R
GWB: 3 - D, 4 - R
Clinton: 8 - D, 2 - R
GHWB: 2 - D, 1 - R
Reagan: 11 - D, 4 - R
TOTALS: 29 - D, 16 - R
While by no means a comprehensive review, just looking at the Legislative Branch convictions seems to indicate no strong bias for Democrats or Republicans. If this bias were as pervasive as you'd like to believe, I would expect the numbers to be skewed strongly against the Republicans. They aren't.
Link: Yeah, I know its wikipedia. You got a better source?
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