PIMCO investment guru Mohammad El-Erian takes to Bloomberg to warn about what he sees as excessive optimism -- or at least complacency-- currently in financial markets.

Judging from market valuations, I sense quite a gap between consensus market expectations and key political and economic realities, especially in the U.S. If the gap isn’t bridged by the validation of the more optimistic expectations, investors may well find that January’s global equity sell-off was just a precursor to a disappointing year for several asset classes, including stocks.

He goes on to talk about a "tense" situation in Washington right now, and the potential for gridlock, causing an inability to tackle the genuinely difficult challenges of the moment.

I am particularly concerned about the surge in joblessness. In the absence of bold structural measures, most of which face political headwinds, we are looking at a period of persistently high unemployment that will disproportionately affect the young. We risk significant welfare losses and skill erosion, lower labor-market flexibility, and yet another burden on the country’s stretched public finances.

These are consequential political and economic questions. They speak to a more protracted post-crisis resetting of the U.S. economy -- what Pimco labeled last year as a bumpy multiyear journey to a new normal.

What comes after banking crises? Sovereign debt crises.

All this is consistent with the academic literature on post-crisis periods. Such research reminds us of the extent to which massive disruptions -- such as the one experienced in 2007-09 -- expose structural cracks that, at best, can only be masked temporarily by a massive cyclical policy response.

Actually, credit to Morgan Stanley, who was ahead of the curve in predicting that this would be the story of 2010.

They produced this chart last November: