Jason Isbell is speaking out about his decision to require that fans show proof of COVID-19 vaccination or a current negative test in order to attend his shows. It's a requirement that has affected recent performances from the singer — such as his appearance at Austin City Limits Live at the Moody Theater — and will be in place for all shows going forward.

"We're now requiring proof of vaccination or a current negative test to attend all of our shows, indoors or out," Isbell explained in a tweet on Monday (Aug. 9). "If the venue won't allow that, we won't play."

Along with this statement, the singer shared a clip of an MSNBC interview in which he explains in greater detail why he decided to implement this new policy at shows.

"I think the people who work at the venues, and who work in the music business, understand. From everything that I've heard so far, all the response that I've gotten so far from people in the business has been positive," Isbell replied, in response to a question about whether venues support instating new rules regarding COVID-19 safety protocols.

"They understand that we could go back to not working at all, and a lot of these smaller venues, they aren't gonna be able to reopen if they go through another round of shut-downs," he points out.

Instead, Isbell believes that the problem lies in venues facing pressure from politicians and state governors eager to return to full-capacity events without any form COVID-19 safety protocol.

"I think the problem is, they're just getting so much pushback from some of the governors of certain states who wanna kowtow to their political base and try to make people think that their freedom is being encroached upon," he says. "You know, I'm all for freedom, but I think, if you're dead, you don't have any freedoms at all. So it's probably important to stay alive before you start questioning your liberty.

"It's life, and then it's liberty, and then it's the pursuit of happiness," Isbell says. "Those are in order of priority."

The singer's decision to require proof of vaccination or a negative COVID-19 test at his shows' points of entry comes in the wake of an announcement from the global entertainment company Live Nation that states that they'll allow touring artists to require similar rules at their shows. On a local level, two Nashville venues -- The 5 Spot and City Winery -- have also implemented similar restrictions in recent weeks.

Top Country Songs of 2021, Ranked

You'll find much more than just the Top 10 Country Songs of 2021 on this list.

Our team has sourced fans to create 10 superlatives for this mid-year version of the year-end songs list. Best Country Tearjerker? Best Country Baby-Maker? Best Country Breakup Song of 2021? Keith Urban, Carly Pearce, Chris Bandi and more help make up this portion of the Top Country Songs list, while hitmakers like Thomas Rhett and Little Big Town lead the 10 best songs portion.

Did your favorite song of 2021 make this list? To be considered, the song must have been released in 2021 or have actively charted for a portion of the year (see "Wine, Beer, Whiskey"). New artists including Lainey Wilson, Breland and Triston Marez crack the Top 10. Let us know your favorite song of 2021 at Twitter or email, at staff@tasteofcountry.com.