One of the earliest examples of Lincoln's written views on slavery comes from an 1845 letter Lincoln wrote to his friend Williamson Durley, concerning the annexation of Texas. In it, Lincoln said he took no position on annexation, but he added "It is possibly true, to some extent, that with annexation, some slaves may be sent to Texas and continued in slavery, that otherwise might have been liberated. To whatever extent this may be true, I think annexation an evil." He then explained "I hold it to be a paramount duty of us in the free states, due to the Union of the states, and perhaps to liberty itself (paradox though it may seem) to let the slavery of the other states alone; while, on the other hand, I hold it to be equally clear, that we should never knowingly lend ourselves directly or indirectly, to prevent that slavery from dying a natural death—to find new places for it to live in, when it can no longer exist in the old." This view, that slavery would be most efficiently curtailed by preventing its expansion rather than direct abolition, would be consistent for Lincoln throughout his political career leading up to his election as President in 1860.