David Weigel's written a bit about Jeff Bezos' apparent political beliefs—he seems to like low taxes and social liberalism, and has put more money behind the latter than the former—but it's also worth looking at Amazon's corporate activities.
Here's how Amazon's PAC spending breaks down:
There's a tilt toward Democrats in recent cycles, a tilt that's especially noteworthy in the 2010 and 2012 election cycles when it seemed clear that Republicans were going to win. Big business usually spreads money around, but tends to favor incumbents and likely winners. Of course one factor biasing Amazon toward Democrats might be that it's based in Seattle. Members of Congress are generally supportive of hometown industries, and in turn companies tend to support hometown incumbents. The more powerful Patty Murray becomes, the more helpful she can be to Amazon. So a useful comparison is to Microsoft, another Seattle-based tech company:
You can see that Microsoft spends a lot more on politics than Amazon, and also spends it in a more Republican way. Democrats got the bulk of Microsoft's money during the two terms that they controlled the House of Representatives, but otherwise the GOP takes the cake.
Alternatively, we can compare Amazon to Wal-Mart, its biggest retail competitor:
Again what's striking here is the sheer difference in scale. Back in 2004, Wal-Mart gave the overwhelming preponderance of its money to Republicans. Even so, Wal-Mart gave more money to Democrats that year as Amazon has given to both parties combined in its highest spending years. All of which is to say that while Amazon certainly minds the store in Washington, it's not a particularly politically engaged company as far as these things go. Or at least it hasn't been until its CEO became the owner of the local newspaper in the nation's capital.