Why is Obama playing hide and seek on cap and trade?

I was just reading a copy of Tuesday's Financial Times, and I came across an article by Edward Luce that seems highly relevant to the question I asked in my Wednesday post entitled, "Did Obama oil spill speech reveal hidden White House energy agenda?".

Prior to the speech Tuesday night, Luce had tried to anticipate what Obama would want to say:

But Mr Obama's larger objective from tonight's address will be to turn the catastrophe to his advantage by painting it as an overwhelming argument for putting a price on carbon in the US.

According to senior Democratic officials on Capitol Hill, he intends to urge the Senate to pass an energy bill that would include some sort of mechanism for pricing carbon, probably a cap and trade system. This follows a deterioration in the Senate bill's prospects after it lost the support of its sole Republican backer, Lindsey Graham, the senator from South Carolina, in April. The House of Representatives passed a cap and trade bill last year.

Following the speech, I wrote: "The fact that Obama did not push for a carbon tax, a gasoline tax, or a carbon trading plan last night was surely significant."  In the post, I explained how Obama even appeared to have used the speech as an opportunity to back peddle on this key issue.  And I attempted to answer the question: Why?