My original analysis of the S&P began on the daily chart but I'm gonna use the 4-Hour chart to better illustrate my point.
On the daily chart, a demand level was formed during the mid-part of July. I marked out a specific point but that whole breakout area can be considered underlying support.
What I see here is that we are still in a major uptrend, despite what has happened these past few months. In this case, however, I still think that the corrective downmove still has some room to run. With that being said, if price is able to clear out this current supply zone (4000-4075), then I see price getting up to the 4160-4200 area. This may be the more likely scenario since daily demand appears to be in control. However, if weakness occurs at the present level (which is a possibility since we're hitting supply), then I don't see any significant demand coming into the market until we hit the 2900 area.
Conclusion: From a long-term perspective, this is a wait-and-see type of deal. For the short-term trader, there are many opportunities to be found whichever direction prices move. One opportunity I see is a long at 4020.