The charts I will show of the Dow will be reminiscent to those who have seen my work over the past 15-20 years in various media and sites. Range bisections from previous extreme levels are powerful price support and resistance markers, as are divisions of that bisection. For very long term charts with huge price moves, logarithmic (percent) charts work best.
The first chart shows the Dow from the 1932 low bisecting the great sentiment range from the A/D high of 1965 to the A/D low of 1982. The parallel lines 50% above and below the median and the extreme parallels have been active at most of the highs and lows of this quarterly (three month) chart. From 1987 to 1995 the median line resisted the advance of the Dow. Then it broke through in a powerful bull market and ran up almost to the extreme in January 2000. Thus 2000 was the beginning of weakness in a very long term bull move from 1932. By 2002 the Dow fell back to the median line and then rallied again up towards the 3/4 line but fell short in 2007. More weakness. After falling below the 1/4 line in 2008/09, the Dow rallied up until this year but failed to reach the median line. Thus we have three instances of failure. Also notable is that this year's high was just short of the rally high into May of 2001 from the highs of January and September 2000. A shorter term arithmetic fork shows that failure below the median from the 2002 low through the 2007-2008 range.
This is basic chart analysis requiring no rocket science oscillators or other indicators. The Dow looks sick since 2000 and could fall to a level of 6000 very easily. Even at that level it could still be bullish.