Market Extra: The S&P 500 fights to hold above a short-term line in the sand of bullish momentum

The wheels appear to be slowly coming off the bull wagon for U.S. stocks, at least in the near term.

The broad-market S&P 500 indexSPX notched its sixth decline in seven sessions Tuesday, according to data compiled by Dow Jones Market Data.

On top of that, the S&P 500 has been struggling to keep aloft of its 50-day moving average, which…