A near perfect test of that downward trendline again this morning, and here we go. 4300 is still a crucial level. Notice how many times the market has tested below this level, but closed back above it. Another close below this level would strongly suggest trend continuation to the down side.
That being said, we have a slew of economic reports and Fed chair testimony the rest of this week, so things could turn on a dime. Keep your wits about you, and be open minded to changing information.