Quinnipiac University Poll -- done between April 26th and 29th of a national sample of 1,044 voters, with a 3.5 point margin of error.
Morning Consult Poll -- done between April 22nd and 28th of a national sample of 15,475 registered voters, with a 1 point margin of error.
CNN / SSRS Poll -- done between April 25th and 28th of a national sample of 1,007 adults, with a 3.8 point margin of error.