I thought that the political advertising for the Presidency had abated in Michigan. The spending has begun on House races.
If President Obama is up 6% in Michigan on a Likely Voters screen a little over a month from Labor Day, then Michigan is on the fringe of contention before the usual political drives that Big Labor coordinates with the Democratic Party and vote-getting drives at the state's giant universities at U-Michigan, Michigan State, Wayne State, and Central Michigan.
The Democratic strategy for success in Michigan is to force the political reality away from the "likely voters" screen. Democrats win big with large turnout in Michigan. Relevance for other states: it's the same with Pennsylvania, Democrats need a strong turnout to win Ohio and can do so reliably, and Democrats need unusually-high turnout to win statewide elections of any kind in Indiana.
If Michigan is a swing state in the Presidential election it is on the fringe of contention.