There appears to be a rising sense among Congressional Democrats that Obama is failing to rally the public behind the Libya mission because he has failed to clearly spell out what a murderous actor Gaddafi has been over the years — and they want Obama to rectify that in his speech tonight.

Senator Robert Menendez of New Jersey will release a statement today calling on Obama to clearly spell out in his speech that Gaddafi was responsible for the bombing of Pan Am flight 103, and to identify him as a terrorist in the same league as Bin Laden. Menendez’s statement:

“Qaddafi is a terrorist — the moral equivalent of Osama bin Laden — a man who ordered the bombing of Pan Am Flight 103, which killed 270, including 34 New Jerseyans, and who in 2009 swapped a lucrative oil deal in exchange for the release of the convicted Pan Am bomber. A man President Ronald Reagan referred to as ‘this mad dog of the Middle East’ because of his relentless instigation of and support for terrorism. A man who has trained terrorists in North Africa and has proven that his reign of terror extends well beyond his own national and regional borders. A man who referred to the 1985 slaughter of innocent travelers, including an eleven-year-old American child, by terrorists at the Rome and Vienna airports as a ‘noble act.’ There is no question that, if given the chance, Qaddafi will continue to support terrorism and, therefore, continue to threaten Americans at home and abroad. That is why a Libyan no fly zone is not only in the interest of the international community, but is also in the national security interest of the United States.”

Polls have shown relatively tepid support for the Libya mission. Menendez’s statement is a sign that Dems are growing increasingly uneasy with the case that Obama has made for the mission, and that they increasingly want him to paint Gaddafi as a murderous figure on a moral par with the masterminds behind the 9/11 acts. If Obama were to follow this advice, however, it would risk making it tougher for him to continue to insist that removing Gaddafi should not be the goal of the mission.