http://projects.vpr.org/vpr-vermont-pbs-2020-polls-september
September 3-15
586 likely voters
MoE: 4%
Changes with February 4-10 poll
Welch 57%
Berry 18%
Other/not sure/no opinion 6%
No one/not voting on this item 6%
Becker (I) 2%
Helali (Communist) 1%
Horne (I) 1%
Orr (I) 0%
Trudell (I) 0%
"If Phil Scott were to challenge Sen. Patrick Leahy in the next Senate election, would you favor Scott or Leahy? "
Scott 41%
Leahy 38%
Neither 7%
Not sure/don't remember 15%
Although I highly doubt Scott could win a Senate race as a Republican, he could pull it off if he ran as an independent (look at Bernie Sanders, after all). At any rate, Leahy needs to retire in 2022. He is the longest serving member of the Senate, and has been in office for 45 years by now. To put things into perspective as to how long he's been there: Leahy's predecessor George Aiken has been dead for 36 years.
I expect he'll retire anyway, but from a tactical standpoint, Leahy may be an electorally stronger candidate against Scott than a fresh Democratic face. It wasn't always so, but he's not resisted progressive trends in his state.