If you look at the graph you will see that as the summer progressed and the attacks by Obama against Romney went largely unanswered,the linesseparated and Obama increased his lead. So, I agree with your assessment.
You might recall that this is exactly what Dick Morris did before the 96 election to the Republicans so that by the time Bob Dole got the nomination and some money,he never had a chance either.
My view is that the Republicans should get on the radio now as the cheapest place from which to snipe and relentlessly attack the Obama administration and, working up to the midterm elections in 2014, Harry Reid and the Minority Leader of the house and demonize them for a welcome change. Although we will not have the media echoing these charges so that the landscape will not look like 2008 in which the whole world was blaming George Bush for everything since original sin, at least we may have a fighting chance.
When I deplore is the tendency among the conservatives on these threads no less than from the Republican establishment to advance their worldview from the results of this election. We need real data and we do not have any yet, at least not much to tell us why we could not get out the vote. This graph tells us that there was not any vote to get out but it does not tell us why and my surmise about unanswered attacks in the summer is only that.
Above all, we must maintain open minds and not let ideology drive us in the wrong direction. I want the answer to be that we should move to the right but I want that answer to come from real data and not from some talking head.
I don't believe that would run afoul of any of the Constitutional Amendments passed so far, they don't speak to the issue.
Another way to take it to the degenerate communist baby killers is for the GOP House leader to start every House session with a count of how many black babies were aborted the day before.
Fight the communists effectively and they will scurry back under the rocks they crawled out from.