No doubt, there will be many brushback pitches during the confirmation process of Brett Kavanaugh--it will truly be a rough ride (to mix a metaphor)--but I am almost certain that he will eventually be confirmed. For one thing, red-state Democrats who are up for re-election in 2018--Joe Manchin of West Virginia; Joe Donnelly of Indiana; and Claire McCaskill of Missouri--will be under intense pressure to break ranks with Chuck Schumer, and vote according to the desires of their constituents. And John Tester of Montana may also vote for confirmation. And I am really unconvinced that Susan Collins (of Maine) will vote against this nominee. Her recent proclamation that she could not vote for anyone who would challenge Roe v. Wade was likely just cover for the fact that she will probably be inclined to vote for this nominee; and, since Judge Kavanaugh has not (and presumably, will not) make an unambiguous statement in this regard, she can then tell her constituents, "Well, I voted for a man who did not say anything about voting to overturn Roe. So it is possible that Judge Kavanaugh may receive 50 Republican votes, plus a handful of Democratic votes. Comments?
It seems more likely than not he will be narrowly confirmed, though your suggestion is really a best case scenario for republicans I think, but I wouldn't place any bets. A Pence tiebreaker would be unsurprising. Abortion is just one issue. This judge has a long history which means more opportunity for controversy and delays (which is why McConnell wanted a different nominee), and another issue is that Trump seems to have chosen this nominee based upon the fact that he is opposed to the president being investigated while in office. If Kavanaugh performs poorly when questioned on this issue, it will be easier to vote against him. And given that his confirmation process is likely to be lengthy, public opinion could change or the confirmation vote could even be after the election, and that's in addition to the argument that democrats want to use the McConnell Rule to wait until after the election to confirm - and by then the math could change. The last part is a minor point though, we know that McConnell will fight dirty to get his way.
Most of your post is quite thoughtful. But I would take exception to this part of it. The so-called "McConnell Rule" never applied to the midterms; only to presidential-election years: (What Senator McConnell actually said was that, "[t]he American people should have a voice in the selection of their next Supreme Court Justice. Therefore, this vacancy should not be filled until we have a new president.") Otherwise, we could never have a SCOTUS nomination in even-numbered years. And several of the sitting justices were nominated in even-numbered years.
I know republicans conveniently take that exception. And really your mention of how it would disallow nominations half of the time is the best argument I've seen against it (though not quite persuasive, who cares if it's half the time or 1/4 of the time, some things only happen periodically and McConnell was perfectly willing to deny SCOTUS a justice for over a year, and the same could happen via midterms). On the other hand, if you were able to remove your partisan lens, you would notice that the argument McConnell used to deny Obama's nominee a hearing for over a year applies just as much to senate elections as presidential ones, since both affect who can become a justice and both involve consulting with the American people via elections. There's no meaningful difference, only a partisan one of wanting to use rules only when they help you.
To label it, pejoratively, as "convenient" is to overlook the fact that Sen. McConnell said precisely that (i.e. that this applied to presidential-election years only.) Those who wish to apply this "rule" more broadly are corrupting the intent of it. It is possible, indeed, to make a reasonable argument that Sen. McConnell acted capriciously--and wrongly--in denying Merrick Garland so much as a hearing. But two wrongs do not equal one right. And mere revenge is really not a serious virtue, in my opinion. Those who are saying that the Senate should not confirm any nominee of this president are saying that we should have an eight-member High Court (leading, inevitably, to many tie votes) for at least two-and-a-half years--and perhaps for six-and-a-half years.
I would not wish to see quotas (for Catholics, Jews, or any other group). This sounds, to me, too much like affirmative action.
Just follow the constitution and let the chips fall where they may. Anyways, if the democrats take the senate, the 60 rule will be put back in force before the next legislature is convened.
