Caveats, caveats, caveats. But is something happening for the Democrats in the national generic ballot?

Nate Silver says that the congressional generic may be understating the Democrats’ strength. But it’s starting to look like that number itself may be shifting. Over the last week, five polling organizations have come out showing the Democrats 1 point ahead of the Republicans. Those are Reuters/Ipsos, Gallup, Zogby, Yougov and PPP. And as you can see from the chart below, it’s actually more of a Republican drop than the Democrats rising, though it’s a bit of both. And that suggests that it’s not just a matter of Dems coming home as the election heats up.

Our chart may actually slightly understate the trend because while we collect so-called Internet polls in our poll data sets, our charts and averages do not include those by default. If you change the filter setting and include them — which means putting Zogby and Yougov back in — the chart looks like this.