Cancer sucks. It is a terrible thing, and I’ve known several people with it. Some saw it go into remission. Some did not. From basic human empathy, I do hope that Senator McCain receives a successful course of treatment. I had the chance to ask him an unmoderated question when he was running in 2008, which he answered fairly (and humorously), though with a solid dose of spin to boost it. In 2000 when I was a New Hampshire independent and thus could pick which primary I wanted to vote in (and Gore had the Democratic side locked up), I voted for McCain over Bush for Republican nominee. I think had 2000-era John McCain ended up being president instead of Dubya, we would have all been better off — though of course President Gore would have been far better.
However…
Contingency planning does not mean ‘hoping it happens.’ The US military, I have heard, has officers-in-training draw up academic contingency plans for sudden and unexpected wars against the unlikeliest of foes, including close allies and laughably outmatched microstates. Having a contingency plan ready means that if something does happen, you’re ready for it. So, under the assumption that, say, Senator McCain resigns his seat to focus on his successful recuperation and years of happy post-Senate time with his family, let’s proceed.
The immediate impact on the Senate is minor. Arizona has a Republican governor, and even if it didn’t, Arizona’s law on Senate replacements specifies that the replacement must be of the same political party as the departing Senator anyway. Nothing says the governor can’t appoint himself — but Doug Ducey might well think he’d have a better chance by running as an incumbent governor, away from Washington and The Accidental Occupant, instead of running as a one-year self-appointed Senator.
The obvious choice is Kelli ‘Chemtrail’ Ward. She’s already running against Flake, so putting her into the other seat would remove a strain on Flake (though some other Tealiban type might primary Flake anyway). I’m not sufficiently up on Arizona politics to know much more; if anyone has suggestions in the comments, please share (or if you know some names who might run on the Democratic side, given a second opening). In the meantime, this article looks like it’s got a good rundown of the possibilities on the Republican side.
The more important impact is that suddenly there are two Senate seats up in 2018, not just one. In a year where Democrats have few places to go on offense, that’s a significant factor. Hillary lost Arizona by less than 4%, and the demographics continue to favor Democrats, with a significantly minority-majority under-30 population continuing to grow with every passing year — while the Accidental Occupant continues to drive Democratic turnout. Now, taking any seat in Arizona is pretty much dependent on getting a strong Democratic wave in 2018, be very sure of that. But if Republicans sit on their hands to show their unhappiness about not getting their wishlist granted, while Democrats are mobilized in opposition, it could happen. And once Arizona starts turning blue, it will happen very, very rapidly, and not swing back for a long, long time. Same with Texas, but the Republican voter-suppression efforts there may delay it… for a while.
So what’s the impact of one more seat? Well, at the low end, it could mitigate losses elsewhere — incumbent Senators not from the president’s party tend to do well in off-years, but there’s still several Democratic Senators up in some very red states in 2018 (North Dakota, Indiana, Montana, Missouri, and West Virginia come to mind). All of them are savvy competitors who can hold their ground with a strong campaign (and continued buffoonery from Donnie), but taking some Republican dollars away from them and into Arizona can only help. But at the high end, well…
Imagine winning Nevada, two in Arizona… and then taking Texas, where Cruz has a terrible popularity rating and at least one poll has him losing or tied with a Democratic candidate. Get a net gain of 3, and two things happen. One, Democrats are set up for a fantastic decade-plus in the Senate with rich targets in the next two cycles in a row. Two… well, The Turtle established that it’s completely fair game for the Senate to completely refuse to consider nominees coming from the White House, didn’t he? Obviously, given the seats up in 2018, ‘holding serve’ is itself a tough goal to aim for… but a fourth target seat for 2018 makes the ‘blue wave’ outcome all the more reachable.