Fillmore's strength proved to be chiefly in the South. His vigorous execution of the fugitive slave law had been more potent than his unsparing use of patronage; and when the Whig convention assembled at Baltimore on June 16 the question whether that law should be declared a finality became of supreme importance. Fillmore could not stand on an anti-slavery platform, and a majority of the New Yorkers refused their consent to any sacrifice of principle. But, in spite of their protest, the influence of a solid southern delegation, backed by the marvellous eloquence of Rufus Choate, forced the passage of a resolution declaring that "the compromise acts, the act known as the fugitive slave law included, are received and acquiesced in by the Whig party of the United States as a settlement in principle and substance of the dangerous and exciting questions which they embrace. We insist upon their strict enforcement; and we deprecate all further agitation of the question thus settled, as dangerous to our peace, and will discountenance all efforts to continue or renew such agitation whenever, wherever, or however the attempt may be made." A roll call developed sixty-six votes in the negative, all from the North, and one-third of them from New York.

This was a Fillmore-Webster platform, and the first ballot gave them a majority of the votes cast, Fillmore having 133, Webster 29, Scott 131. The number necessary to a choice was 147. The activity of the Fillmore delegates, therefore, centred in an effort to concentrate the votes of the President and his secretary of state. Both were in Washington, their relations were cordial, and an adjournment of the convention over Sunday gave abundant opportunity to negotiate. When it became manifest that Webster's friends would not go to Fillmore, an extraordinary effort was made to bring the President's votes to Webster. This was agreeable to Fillmore, who placed a letter of withdrawal in the hands of a Buffalo delegate to be used whenever he deemed it proper. But twenty-two Southern men declined to be transferred, while the most piteous appeals to the Scott men of New York met with cold refusals. They professed any amount of duty to their party, but as regards the Fillmore combine they were implacable. They would listen to no terms of compromise while their great enemy remained in the field. Meantime, the Scott managers had not been asleep. In the contest over the platform, certain Southern delegates had agreed to vote for Scott whenever Fillmore reached his finish, provided Scott's friends supported the fugitive slave plank; and these delegates, amidst the wildest excitement, now began changing their votes to the hero of Lundy's Lane. On the fifty-third ballot, the soldier had twenty-six majority, the vote standing: Scott, 159; Fillmore, 112; Webster, 21.

The prophecy of Hamilton Fish was fulfilled. Fillmore now realised, if never before, "the tremendous mistakes he had made." Upon his election as Vice President, and especially after dreams of the White House began to dazzle him, he seemed to sacrifice old friends and cherished principles without a scruple. Until then, the Buffalo statesman had been as pronounced upon the slavery question as Seward; and after he became President, with the tremendous influence of Daniel Webster driving him on, it was not believed that he would violate the principles of a lifetime by approving a fugitive slave law, revolting to the rapidly growing sentiment of justice and humanity toward the slave. But, unlike Webster, the President manifested no feeling of chagrin or disappointment over the result at Baltimore. Throughout the campaign and during the balance of his term of office he bore himself with courage and with dignity. Indeed, his equanimity seemed almost like the fortitude of fatalism. No doubt, he was sustained by the conviction that the compromise measures had avoided civil war, and by the feeling that if he had erred, Clay and Webster had likewise erred; but he could have had no presentiment of the depth of the retirement to which he was destined. He was to reappear, in 1856, as a presidential candidate of the Americans; and, after civil war had rent the country in twain, his sympathy for the Union was to reveal itself early and with ardour. But the fugitive slave law, which, next to treason itself, had become the most offensive act during the ante-war crisis, filled the minds of men with a growing dislike of the one whose pen gave it life, and, in spite of his high character, his long public career, and his eminence as a citizen, he was associated with Pierce and Buchanan, who, as Northern men, were believed to have surrendered to Southern dictation.[127]

In the national convention at Baltimore, which met June 1, 1852, the New York Democrats were likewise destined to suffer by their divisions. Lewis Cass, James Buchanan, and Stephen A. Douglas were the leading candidates; though William L. Marcy and Daniel S. Dickinson also had presidential ambitions. Marcy was a man of different mould from Dickinson.[128] With great mental resources, rare administrative ability, consummate capacity in undermining enemies, and an intuitive sagacity in the selection of friends, Marcy was an opponent to be dreaded. After the experiences of 1847 and 1848, he had bitterly denounced the Barnburners, refusing even to join Seymour in 1849 in his heroic efforts to reunite the party; but when the Barnburners, influenced by the Utica statesman, began talking of him for President in 1852 he quickly put himself in accord with that wing of his party. Instantly, this became a call to battle. The Hunkers, provoked at his apostacy and encouraged by the continued distrust of many Barnburners, made a desperate effort, under the leadership of Dickinson, to secure a majority of the delegates for Cass. The plastic hand of Horatio Seymour, however, quickly kneaded the doubting Barnburners into Marcy advocates; and when the contest ended the New York delegation stood twenty-three for Marcy and thirteen for Cass.

Dickinson, who had been a steadfast friend of the South, relied with confidence upon Virginia and other Southern States whenever success with Cass seemed impossible. On the other hand, Marcy expected a transfer of support from Buchanan and Douglas if the break came. On the first ballot Cass had 116, Buchanan 93, Douglas 20, and Marcy 27; necessary to a choice, 188. As chairman of the New York delegation, Horatio Seymour held Marcy's vote practically intact through thirty-three ballots; but, on the thirty-fourth, he dropped to 23, and Virginia cast its fifteen votes for Dickinson, who, up to that time, had been honoured only with the vote of a solitary delegate. In the midst of some applause, the New Yorker, who was himself a delegate, thanked his Virginia friends for the compliment, but declared that his adherence to Cass could not be shaken.[129] Dickinson had carefully arranged for this vote. The day before, in the presence of the Virginia delegation, he had asked Henry B. Stanton's opinion of his ability to carry New York. "You or Marcy or any man nominated can carry New York," was the laconic reply. Dickinson followed Stanton out of the room to thank him for his courtesy, but regretted he did not confine his answer to him alone. After Virginia's vote Dickinson again sought Stanton's opinion as to its adherence. "It is simply a compliment," was the reply, "and will leave you on the next ballot," which it did, going to Franklin Pierce. "Dickinson's friends used to assert," continued Stanton, "that he threw away the Presidency on this occasion. I happened to know better. He never stood for a moment where he could control the Virginia vote—the hinge whereon all was to turn."[130]

In the meantime Marcy moved up to 44. It had been evident for two days that the favourite candidates could not win, and for the next thirteen ballots, amidst the greatest noise and confusion, the convention sought to discover the wisest course to pursue. Seymour endeavoured to side-track the "dark horse" movement by turning the tide to Marcy, whose vote kept steadily rising. When, on the forty-fifth ballot, he reached 97, the New York delegation retired for consultation. Seymour at once moved that the State vote solidly for Marcy; but protests fell so thick, exploding like bombshells, that he soon withdrew the motion. This ended Marcy's chances.[131] On the forty-ninth ballot, North Carolina started the stampede to Pierce, who received 282 votes to 6 for all others. Later in the day, the convention nominated William R. King of Alabama for Vice President, and adopted a platform, declaring that "the Democratic party of the Union will abide by, and adhere to, a faithful execution of the acts known as the compromise measures settled by the last Congress—the act for reclaiming fugitive slaves from service of labour included; which act, being designed to carry out an express provision of the Constitution, cannot with fidelity thereto be repealed, nor so changed as to destroy or impair its efficiency."

Some time before the convention it was suggested, with Marcy's approval, that the New York delegation should vote as a unit for Dickinson if he proved the stronger candidate outside the State, and, upon the same condition, a solid delegation should vote for Marcy. This proposition did not reach Dickinson until his leading friends had committed themselves by a second choice; but, in speaking of the matter to Thurlow Weed ten years afterward, Dickinson said that had it come in time he would cheerfully have accepted it, adding that whatever may have been his opinion in 1852, he now knew it would have resulted in Marcy's nomination.

The disturbance among the New York delegates at Baltimore had its influence at Syracuse when the Democratic state convention assembled on September 1. Seymour was the leading candidate for governor, and Dickinson opposed him with a bitterness born of a desire for revenge. The night before the convention Seymour's chances were pronounced desperate. Whatever disappointments had come at Baltimore were laid at his door. Seymour made Cass' defeat possible; Seymour refused to help Buchanan; Seymour was responsible for a dark horse; Seymour filled Marcy's friends with hopes of ultimate victory, only to heighten their disappointment in the end. All these allegations were merely founded upon his steadfastness to Marcy, and he might have answered that everything had been done with the approval of a majority of the New York delegation. But Dickinson was no match for the Utica statesman. Seymour's whole life had been a training for such a contest. As Roscoe Conkling said of him many years later, he had sat at the feet of Edwin Croswell and measured swords with Thurlow Weed. He was one of the men who do not lose the character of good fighters because they are excellent negotiators. Even the cool-headed and astute John Van Buren, who joined Dickinson in his support of John P. Beekman of New York City for governor, found that Seymour could cut deeply when he chose to wield a blade.[132] Seymour, moreover, gave his friends great satisfaction by the energy with which he entered the gubernatorial contest. When the first ballot was announced he had 59 votes to Beekman's 7, with only 64 necessary to a choice. On the second ballot, the Utican had 78 and Beekman 3. This concluded the convention's contest. Sanford E. Church was then renominated for lieutenant-governor, and the Baltimore platform approved.

The Whig state convention met at Syracuse on September 22 and promptly renominated Washington Hunt for governor by acclamation. Raymond wanted it, and Greeley, in a letter to Weed, admitted an ambition, while a strong sentiment existed for George W. Patterson. Hunt had veered toward Fillmore's way of thinking. "The closing paragraphs of his message are a beggarly petition to the South," wrote George Dawson, the quaint, forceful associate of Weed upon the Evening Journal.[133] But Hunt's administration had been quiet and satisfactory, and there was little disposition to drop him. He did not have the patience of Hamilton Fish, but he resembled him in moderation of speech.

William Kent, a son of the Chancellor, received the nomination for lieutenant-governor. Kent was a scholarly, able lawyer. He had served five years upon the circuit bench by appointment of Governor Seward. He co-operated with Benjamin F. Butler in the organisation of the law school of the New York University, becoming one of its original lecturers, and was subsequently called to Harvard as a professor of law. Like his distinguished father he was a man of pure character, and of singular simplicity and gentleness.