I’m not here to wank about my ideas of how campaigns should be run, but it seems obvious that a lot of winning an election is about making the election revolve around issues where your side has the upper hand. Republicans were smart, if shameful, about this for many years. They made the 1988 race about Willie Horton, for example.
Whatever one thinks of Paul Ryan, there’s no denying that his selection made the future of Medicare a reasonably big issue in this race. Medicare is a popular government program that was created by Democrats. Voters are more inclined to trust Democrats on the issue. Never mind that, yes, Paul Ryan’s plan would replace it with vouchers in reality, or that Republicans have run a lot of ads lying about that and accusing Obama of cutting it. That may or may not matter. Medicare is a good issue for Democrats and a bad one for Republicans. Full stop.
If you look at the charts, you’ll see that Obama has led on the issue the entire race, that it did tighten a bit after the selection of Ryan, but that Obama now has a comfortable lead on the issue again.
My guess, though, is that in June and July, even if voters favored Obama on Medicare, they weren’t thinking about it much.