The problem is that the Constitution leaves confirmation decisions to the political process, with no legal standard. President Obama certainly has the constitutional power to nominate someone, even in an election year (just as President Bush had the power to do so in 1992, if there had been a vacancy). The Senate certainly has the constitutional power to refuse its “consent” to the candidacy, even if this means waiting for a year until after the election. The President was elected by the people, who conferred on him the power to nominate. The Senators were elected by the people, who conferred on them the power to consent or to refuse consent.
The Constitution deliberately leaves these decisions to the political branches, and to the political process within the political branches — with the ultimate constraint being the voters, who can punish either party if they think the party behaves unreasonably or unwisely in this process (note again political criteria, not legal ones).
Now longstanding, broadly adhered to precedents matter even in the political process. Perhaps this respect for tradition and desire for consistency over time is a feature of human nature generally, but it certainly is a feature of American politics, at least some in measure. If there had been a constant practice, for instance, of Senators agreeing to vote for judicial nominees unless those nominees were obviously corrupt or intellectually or professionally unqualified, then there likely would be a strong political backlash to an attempt to depart from this practice. Likewise, if there had been a constant practice of Senators agreeing that every nominee should be considered without regard to there being a looming election, many senators today would be reluctant to buck that practice.
But there seems to be no such practice (see, e.g., Miguel Estrada & Benjamin Wittes’ “There no longer are any rules in the Supreme Court nomination process column in Friday’s post), as then-Senator Biden’s remarks illustrate. And in the absence of such a practice, we come down to more results-oriented politics. Senators, and the voters who evaluate the senators’ performance, consider the usual political considerations that apply to any proposal — say, to a treaty (to given another example of what the President proposes and what the Senate must approve or reject), or to a bill coming from the House of Representatives (where another house proposes and the Senate must approve or reject).
The senators ask: Will approving the proposed candidate, treaty, or bill be good for America, as I see it? (This is similar to the President’s decision in selecting an appointee, or deciding whether to send a treaty to the Senate.) If I say no, how much harm will delay cause? If say no, am I likely to get someone or something better instead? If I say no, will this make it more likely that the other side will retaliate when the tables are turned, or is it likely that the other side will do what it wants when the tables are turned regardless of what I will do? Has the other side done favors for me in the past that I feel obligated to repay? What political pushback will I face if I make either decision?
In making these political decisions, it seems reasonable to consider what Senator Biden said in 1992, President Obama’s votes against Chief Justice Roberts and for the filibuster of Justice Alito, and other similar matters. And when the parties are competing with each other, and are offering the voters competing visions of policy and law, it makes sense for a party to refuse to impose on itself a constraint — one not mandated by the Constitution — that the other party has not agreed to impose on itself in turn.