New poll of 2000 voters released yesterday. Support for the secession of one's own state is at 39.3%, both Dems and Republicans. The poll doesn't say how many are undecided on secession, but a 2016 poll had 15% undecided, which could make both proponents and opponents a minority in this case.
The results would be much better if they had asked about joining a group of like-minded states to secede. Some states are landlocked, so their residents aren't likely to want to be the first state to secede.
If the US average is 39.3 percent, then some states are majority in favor. It only takes Texas seceding to force other red states to recognize that they can't win elections without Texas, so they will have to secede too. We don't need a national majority. We just need a majority in a key state like Alabama, Louisiana, greater Idaho, or Texas.
Here's the wording of the poll question: "If [Candidate Respondent Did Not Support] wins the presidency, how likely would you be to support the idea that your state should formally request to secede from the United States?" https://www.ktsa.com/poll-near....ly-40-percent-of-lik