In the midst of tense negotiations to raise the debt ceiling, President Obama participated in a conference call with a group of college student body presidents from across the country on Tuesday, the Huffington Post reports. Although the call was not announced in advance–indeed, there was little-to-no public mentioning of it–White House sources confirmed the president took time to speak with students who are concerned that young people would shoulder much of the burden of spending cuts in a deal to raise the debt ceiling…