It is often said that bull markets take the stairs up and the elevator down. When we observe the 30-minute SPY chart below spanning the month of February 2013, you will note how bulls methodically turned the 151.50 level from resistance into support. The same might be said for, roughly, the 152.50 zone of late.
However, given the steep rise throughout the month of January it is worth remembering that complacency is an omnipresent trap in the market, seemingly lurking in the shadows just when you thought you had effectively sent it to its demise.
In other words, weakness down away from 152.50 would represent a change in short-term character of the market. Given the action in 2013 thus far, that is still merely a wish for bears and underinvested bulls until it actually happens. Nonetheless, the rally to begin this year is still taking the stairs up, albeit with a much curvier staircase prone to accidents happening.