On the court , McLean became known as an opponent of slavery , and he was frequently mentioned as a presidential candidate for various parties . McLean received the support of delegates at the 1848 Whig National Convention , the 1856 Republican National Convention , and the 1860 Republican National Convention . He was one of two justices to dissent in the landmark case of '' Dred Scott v. Sandford '' . McLean served on the court until his death in 1861
1860 Republican National Convention
1860 Republican National Convention
John McLean