Over the past 3 years, the only support level that has mattered for the S&P500 was the 100 Day Moving Average: every single time the S&P has approached, or breached, this trendline, the result has been a bout of buying pushing it right above, and keeping it in the clearly visible upward channel since 2012.
The S&P is now just a few points away from breaching the 100 DMA again.