If ANY state refuses to implement a lockdown order, the pandemic will run its full course, with the maximum number of deaths. Infected people travel happily (remember, 4 out of 5 infected people have no idea) from a cesspool like Texas or Tennessee, they defeat efforts to contain the virus.
I have no hope that these dipshit governors will come to their senses, at least not as long as Trump continues to tell them otherwise. Neighboring states that do have lockdown orders in place should stop those people at the border.
There's some evidence that lockdowns in OR and WA are having some effect. Though there continue to be new cases, the rate of rise is slowing. Next door in Idaho, there's a huge outbreak in Boise and other cities; until a couple of days ago, their (dumbass fanatical neo-Nazi Republihole) governor said the coronavirus was no big deal and he would never issue a lockdown order. He's since changed his mind--too late.
We also have evidence from China and South Korea that complete lockdowns work. Even Italy is seeing some progress.