What do you think would it take to make liberals realize that there is a threat of Muslim terrorists, despite 9/11 and Fort Hood?
First, there are no liberals in this country. They left town or died off with the advent of the 1960s. "Liberals" (although misguided about domestic policies) were still true patriots and america-first folks.
Since the 1960s, we have been dealing with the america-hating left. For decades they hid behind the label "liberal" until became so unpopular with america they took up their new label, "progressive."
However, they are neither liberal or progressive. They are hardcore american-hating leftist who utterly despise this nation, its founding principles, its founders and, above all, its constitutionally protected freedoms.
With this said, you'd be wasting your time to try to convince so-called libs that islamo-fascism is a threat to us since they don't care and would support any enemy(foreign/domestic) that might actually succeed in putting them in power.
Name one enemy we have fought since Korea that they did not openly and publicly support over our troops and our nation?