"Taken by surprise," as he put it, and unwilling to see the possibility of electing an antislavery senator disappear, Lincoln ordered his backers to cast their votes for Trumbull, ensuring his victory on the next ballot.23 If this episode demonstrated anything, it was that prior political affiliations constituted a major obstacle to antislavery cooperation. The outcome left Lincoln bitterly disappointed. But his willingness to sacrifice personal ambition for political principle reinforced his standing among those opposed to the expansion of slavery."