Just when you thought that Wall Street was safe from European protestors, the Old World streets get flooded again with protestors who fear they won’t continue receiving as much government largess as they were expecting. Both U.S. and European markets fell in early Wednesday’s trading as protests against potential new austerity measures in Belgium, Ireland and Spain brought back memories of those springtime riots in Greece.

Today’s protests raised some major concerns that fiscally challenged countries like Spain will have a hard time mustering the political will to implement much-needed austerity measures. Now, recall that early this year, stocks got knocked for a loop after news that Greece and Portugal were on the verge of fiscal implosion. Since then, the European Central Bank and other major financial players around the globe largely have come to the rescue, but now with political worries reignited, we could be staring at European smackdown, round two.

If we do see Europe’s woes manifest into a more sinister situation, it could mean the end of the recent bull run in both domestic and European stocks. A look above at the charts of the S&P 500 Index and the iShares Europe 350 fund (IEV) clearly show two markets on a rocket run higher -- yet eminently ripe for a pullback.

If you have equity exposure to domestic and/or European stocks (and I certainly do), it behooves you to make sure your stop-loss prices are in place and set to capture gains on any hint of a significant pullback. Let’s face it, stock market gains in 2010 have become much too hard-fought to let slip away, so make sure you’ve determined all of your sell points before protestors in Europe erase your stock market winnings.