At Garfield's request, Senator Conkling met with the president at the White House on March 20 to discuss patronage.  At the Republican National Convention the previous summer, Conkling had backed former president Ulysses S. Grant for a third term and opposed the selection of Garfield.  The president now informed New York's senior senator that he intended to reward those New Yorkers who helped nominate him.  Conkling acquiesced to this political reality, but suggested they be placed in foreign missions.  He came away from the meeting, however, convinced that the vague Garfield had promised to consult him on the appointment of the collector of the New York Customhouse, the most powerful and lucrative patronage position in the country.

Two days later, Garfield named five Conkling supporters to government posts, including Stewart Woodford for the highly sought job as U.S. attorney for the southern district of New York.  The move shocked Blaine, who threatened to resign from the cabinet unless Garfield chose William Robertson for the New York Customhouse.  Its current occupant, Edwin Merritt, who supported civil service reform, would be transferred to the London consulate.

Garfield's acceptance of Blaine's plan made Conkling apoplectic with anger, and provoked protests from Vice President Arthur and reformers irritated at Merritt's removal.  Hoping to appease all sides, Garfield proposed that Merritt stay as port collector, Robertson get Woodford's position as the attorney general for southern New York, and Woodford be assigned to a pleasant diplomatic post.  After Conkling refused to negotiate, Garfield proceeded with the appointment of Robertson as collector of the New York Customhouse.

At that point, Garfield escalated the conflict from a petty squabble over patronage to a noble fight for presidential independence from senatorial tyranny.  The president became determined to "settle the question [of] whether the President is [a] registering clerk of the Senate or the Executive of the United States."  Garfield insisted that the New York customhouse's location at America's primary port invested it with national interest, not merely local concern.  

Newspapers across the country, including Harper's Weekly, supported the president overwhelmingly and began to demonize Conkling.  On May 5, Garfield withdrew all his nominations except for Robertson as New York Customhouse collector.  Behind the scenes, the president used promises of patronage and influence to convince key senators to back his position.  Garfield warned his opponents that they would "henceforth require letters of introduction to the White House."  On May 13, the administration announced it had enough votes for Robertson's confirmation.

On May 16, to the surprise of nearly everyone, Senators Conkling and Platt announced their resignation.  Platt later claimed that the idea was his:  to resign and be vindicated through reelection by the New York legislature.  Conkling left no record, but after several major disappointments, the looming defeat on the patronage question may simply have convinced him to return to his private law practice.  The next day, the Senate approved Robertson's appointment.

In Albany, there was no spontaneous movement to reelect the two senators, and Stalwarts were on the defensive, with some labeling the ploy "childish."  The capital was flooded with petitions opposing the senators' reelection, and Half-Breeds worked around the clock to twist the arms of wavering legislators.  Conkling initially refused to discuss whether he would even seek reelection, but a group of leading Stalwarts finally cajoled the reluctant politician into seeking the seat.  On May 31, the New York legislature met in joint session to decide who would be the state's U.S. senators.  Defections from the Stalwart side and a fractured opposition resulted in a deadlocked legislature that continued through June.  

In early July, two events broke the logjam.  First, a group of Half-Breeds blackmailed Platt into withdrawing after they discovered him in bed with a woman who was not his wife.  Second was the fatal wounding of President Garfield on July 2 by a disgruntled office-seeker.  Already vilified by the press, Conkling's stance of clinging to power over patronage appointments now seemed even more disreputable.  It became obscene when the crazed assassin, Charles Guiteau, claimed that his despair over not receiving a government job reached the breaking point when Conkling resigned on May 16.  Although the senator had no connection with Guiteau, and visited Garfield's bedside (the president lingered until September), the political damage was irreparable.  

On July 8, a Republican caucus met in Albany and decided to nominate one Stalwart, the elderly Congressman Elbridge Lapham, and one Half-Breed, Congressman Warner Miller, both of whom were elected by the full legislature a few weeks later.  After Lapham's election, The New York Time's headline read:  "Roscoe Conkling Beaten."  Thereafter, Conkling became one of New York City's leading lawyers until his death in the blizzard of 1888.  Platt eventually returned to the U.S. Senate in 1896.