In picking a Supreme Court nominee, President Obama faced a strategic political choice: Should he nominate a strong progressive, a nominee of color, and/or a woman to mobilize the Democratic base in advance of the 2016 election? Or was it smarter to pick someone more moderate, someone whom some Republicans had already voted for, and try to force uncomfortable divisions within the fissuring Republican Party.
In nominating Merrick Garland, Obama has clearly decided on the second strategy. And it is surely not a coincidence that Obama made this announcement the day after Trump knocked Rubio out of the presidential race and continued his steady march toward becoming the Republican nominee.
With Trump solidly on path to the nomination, Democrats don't need to worry so much about turning out the base, particularly minority voters. The threat of a Trump presidency should be enough to motivate particularly Hispanic and African-American Democrats to vote. And you can bet that by November, Trump's litany of sexist comments will be repeated so often that most people will know them by heart.
With this problem solved for Democrats, the obvious pivot was to see how they could make life uncomfortable for Republicans. This is why Garland and Sri Srinivasan made it to the top of the shortlist. Both were moderates whom Republicans had voted for in the past.
So now individual Republican senators are faced with a very difficult choice. They can continue to not even grant the guy a hearing, look more and more extremist, and effectively cast their lot with Donald Trump. Or they can decide that a moderate justice is better than anybody either Trump or Clinton might appoint. Of course, they could also continue to wait to see how things develop. Indeed, the most likely scenario is that if Trump or Clinton wins, Garland gets voted in after the November election.
But Republican senators are going to be forced to take public positions now. For Republicans facing tough reelections, opposing a moderate looks particularly bad in light of Trump at the top of the ticket. That is precisely what the pick is designed to accomplish.
This is not a one-off strategic choice for the Democrats. It signals the direction party leaders are likely to move in the years ahead. If Trump is the nominee (as still seems very, very likely), Democrats can effectively take their base for granted, as Obama just did. Clinton can run to the center and then as president continue to push a centrist agenda designed to split Republicans.
And as Trump becomes the standard-bearer for the Republican Party, Republicans in the Senate and elsewhere will have to decide whether they are with him or not. And if Democrats are canny (as Obama and Clinton both are), they will force more difficult choices on Republicans, hammering on the cracks in a Republican coalition that is falling apart.
As I've argued already, I believe we are at the beginning of a coming party realignment that will end with Democrats becoming the party of urban, cosmopolitan business liberalism and Republicans the party of suburban and rural nationalist populism. (For more on the political science underlying this likely realignment scenario, Jennifer Victor has a great explanation at Mischiefs of Faction.)
Obama's decision to nominate Garland seems to me a clear sign that we are moving in this direction. It's an unmistakable Democratic pivot to the center, intended to divide Republicans while taking the base for granted. We are going to see a lot more of this ahead.