Why was lincoln reluctant to issue the emancipation proclamation despite his personal antislavery loyalties?

Lincoln thought of making a colony for freed blacks in Central or South America however the idea was argued by American Negroes and some leaders themselves, hence Lincoln abandoned the idea. He was faced with a great dilemma that he felt the Constitution did not give him or the Congress authority to infringe on a state's right to allow slavery itself. It would also mean that citizenship of a slave would mean to allow blacks to serve in the Civil War as soldiers but he was reluctant to do so. Thus the idea of emancipation occurred. The Emancipation Proclamation would be issued reluctantly because Lincoln knew that this proclamation would be perceived as a humanitarian gesture, resulting in the border states seceding and there will be more serious racial backlash in the northern cities, plus reducing the chances of receiving financial support from England or France to the south.