One of Lincoln’s most important speeches before his Presidency, this address made the case that America’s founders intended to restrict slavery. Lincoln had been invited to speak at Henry Ward Beecher’s church in Brooklyn, but at the request of the New York Young Republicans, the speech was moved to the more capacious Cooper Institute. Lincoln spent months preparing the speech, and the result was a methodical presentation of his historical research. He uses records of the Constitutional Convention, legislation passed by the Founding generation, and statements from the period to build the case that the Republican party’s opposition to the expansion of slavery was not revolutionary, as the Democrats contended, but rather true to the Founders’ vision. The speech was well-received. Not only did it become a rallying cry for the newly formed Republican party, but it helped Lincoln garner support for his presidential campaign in New York, the home state of his party rival William Seward.