President Obama was dealt a defeat by a bipartisan coalition in the House this week. Over 300 Democrats and Republicans voted against a proposal that joined “trade assistance” (TAA) with fast-track trade negotiation authority (TPA). The “usual way” this works, as many have pointed out, is that Democrats want TAA, which helps workers, and Republicans want TPA, which helps presidents promote freer trade.

There’s a lot to unpack here. The loss is a loss for Obama in the sense that Congress rejected an extension of presidential authority. It’s a loss for Obama in the sense that he personally and publicly lobbied (at the last minute) for the TAA/TPA package. But what’s the real message here? I think the real message is somewhere in the weeds of why Obama lost the vote on TAA. There are at least three possible reasons (and of course more than one of them could be true simultaneously.)

The Unions. The AFL-CIO quite visibly broke with President Obama in lobbying against fast-track authority, even when joined to TAA. More to the point, perhaps, the AFL-CIO has been withholding support from, and even talking of supporting primary challengers to, Democratic incumbents who support TPA. This is a big deal, because the AFL-CIO, not to mention other labor unions, represent a significant part of the Democrats’ campaign machinery.

Pelosi. Arguably, Obama’s efforts were undone by Democratic leader Nancy Pelosi’s impassioned, cliffhanger floor speech immediately before the vote in which she announced she would be voting against TAA. This, most Congress-watchers would say, freed rank-and-file Democrats to vote against the measure as well.

The GOP. President Obama has received clear and strong support from Congressional Republicans on TPA (and, by “the usual way” extension, on TAA). This support has, arguably, led to internal defections and punishments within the House GOP caucus. It might have also cost President Obama support among Democrats.

This is real politics, understood by real political scientists. As a classic (and arguably over-cited) example, Richard Fenno (1978) famously argued that politicians have three goals: reelection (first and foremost), power/prestige within Congress, and “good” policy outcomes. If one takes a quick scan above, it’s clear that each of these three goals arguably came into play for Democratic Members in the TPA/TAA votes. The Unions are reelection, Pelosi is party, and the GOP is policy.

What does it all mean? I can’t tell you a pat answer—to me, the search for a pat answer is why political/social science is essentially always down a couple of strokes if not more when approached by the public/pundits. The realities of politics at its best, like any game of high stakes, is that it’s impossible to predict a priori. I can predict with near certainty almost everything about politics, and almost nothing that anybody cares about. This is because rational choice social science is essentially right: you, as a reader, want to know about those things that are hard to predict. Unfortunately for you, you’re pretty smart: most things that you find hard to predict are actually hard to predict. More generally, I can explain to you why things work in certain (sometimes mysterious ways), but I can not show you a reliable crystal ball.

In the end, social science is a lot like meteorology: there is a lot of basic science that is quite hard and, nonetheless, always improving. But at the end of the day, while we can tell you generalities and predict things with more certainty than before, we can’t tell Alanis Morissette with certainty whether it’s going to rain on her wedding day.

In the end, I would bet that TPA fails for now, but whether Obama ends up getting the authority he wants before January 2017 is almost unknowable…for now.

[Cross-posted at Mischiefs of Faction]