Election Year is the confounding factor.
A lot of year left and three whole months until the election. I read an old Yale Hirsch piece on the election cycle and it doesn't seem that the market can't have a nice little shakeout on its way to new all time highs. Also the market is still well ahead of its 4th year average gain. The third year of the cycle historically has had the largest gains.
Here is an interesting set of charts I found on stockcharts.com
Presidential Cycles | Historical Chart Gallery | StockCharts.com

