How pro-Trump became a policy position

There's no question that, prior to last week, President Donald Trump held fairly anti-interventionist views on foreign policy. Breaking dramatically with Bush-era Republican orthodoxy, Trump ran on a message of "America First" and of avoiding spending blood and treasure on adventures overseas. And yet, with last week's Tomahawk missile barrage against the Syrian government in response to a chemical attack on civilians, this administration took a step in the exact opposite direction from Trump's earlier rhetoric.

If Trump was elected by voters who supported non-intervention, wouldn't breaking with that position then cost him support? Online backlash from the "alt-right" certainly led to speculation that the move in Syria would potentially cost Trump his "base." But this all assumes that Trump's voters held anti-interventionist views and therefore gravitated toward him, rather than the other way around: gravitating toward Trump for one reason or another and adopting a more complete, weakly-held slate of Trump views only after the fact.

And indeed, polling suggests that last week's actions in Syria will neither strongly help nor strongly hurt Trump's position, despite plaudits from Hillary Clinton and skeptical tweets from Laura Ingraham. Trump's job approval has remained flat for the last week. But shouldn't Trump's voters be angry with him for doing a 180 on intervention in Syria?

Political science has long tried to tackle a fundamental question of voter behavior: Do voters choose politicians because those politicians hold views that they like, or do voters choose policy positions because they politicians they like say those positions are correct? Do voters have a set of preferences and go searching for a candidate that best fits those preferences, or does it go the other way, where voters pick a candidate because of something emotional or embedded in their identity, and that leader shapes voter views? It's not hard to assume that voters do not have deeply considered views on each and every policy issue before them, but instead perhaps have one or two strongly held views, and then allow their favored political leaders to fill in the gaps on the rest of the issues.

Perhaps no modern political issue tests this question quite like that of Russia and Syria. Indeed, looking at polling data from 2013 on the question of whether or not to engage in military activity in Syria is like looking at polling conducted in an alternate dimension on another planet, with views on these issues having been completely reversed in a very short time span.