Rebel groups across Syria are defying the United States by pledging their allegiance to a group that Washington will designate today a terrorist organization for its alleged links to al-Qaeda. A total of 29 opposition groups, including fighting "brigades" and civilian committees, have signed a petition calling for mass demonstrations in support of Jabhat al-Nusra, an Islamist group which the White House believes is an offshoot of al-Qaeda in Iraq. The petition is promoting the slogan "No to American intervention, for we are all Jabhat al-Nusra" and urges supporters to "raise the Jabhat al-Nusra flag" as a "thank you". "These...