Some days it just doesn’t pay to get up in the morning. Mayor Bloomberg had one of those days on Friday, when everything seemed to go wrong, and go wrong in a way that will keep coming back at him in the months ahead as he seeks a second term.

When the mayor opened his morning papers he read about a nasty incident that took place Thursday at the Adlai Stevenson High School campus in the Bronx. The principal of one of the component small high schools, handpicked by Mr. Bloomberg’s Department of Education, got into a shoving match with a police officer over the arrest of a student. The Stevenson campus is one of the “impact sites,” dangerous schools where the mayor has brought in the police to restore order.

The principal and student ended up in jail, the cop in the hospital, and the mayor’s administration with egg on its face, wrestling with questions over who’s in charge in the most troubled schools. With six principals and the police sharing a building, it was only a matter of time before that type of jurisdictional dispute, which I am told is not uncommon, spun out of control. Two of the mayor’s signature programs, the small high schools and the impact school program, seem somehow less compelling after that ugly incident.

Questions were raised last month about the fate of a new school in the downtown district of Assembly Speaker Sheldon Silver. It was suggested that the plan was being held hostage by the mayor as a means to pressure the speaker to support the proposed Jets stadium on the West Side. The announcement Friday that the school would go forward, rather than ending the speculation, only intensified it.

But that was the least of the mayor’s problems relating to the stadium plan. This project has assumed gargantuan proportion as a campaign issue. Opponents such as Fernando Ferrer and Gif ford Miller were already calling for a public referendum to decide the fate of the stadium project. (Another candidate, C. Virginia Fields, president of Manhattan, said the call for a referendum was “nonsensical.”)

Later on Friday, Cablevision, owners of Madison Square Garden, eager to stop the stadium project to thwart its potential as a competitor for large indoor events, shocked the administration with its offer to purchase the site from the Metropolitan Transportation Authority for $600 million. That is six times the price offered by the Jets. That figure was already the subject of derision by stadium opponents, who said it was far too low.

The administration quickly termed the Cablevision offer “desperate,” but in fact it was brilliant and may indeed kill the Jets stadium. It is politically untenable for the bankrupt MTA to reject an offer that could bring it hundreds of millions more dollars, and it is questionable whether the Jets can match the offer.

Lurking in the background is the bid to obtain the 2012 Olympics for the city, another area that caused the mayor some anguish last week. The dual role of Daniel Doctoroff as a deputy mayor and leader of the NYC 2012 committee was called into question byWNYC radio and the Village Voice. The fact that the mayor self-finances his election campaign has been powerful insulation from charges of campaign finance-related corruption. But the recent coverage suggested that support for the 2012 committee is the favored substitute for campaign contributions to win favorable treatment from the administration.

If the stadium project falters, the mayor warns that the Olympics may be lost. And if the stadium project goes forward but the Olympics are lost anyway – which some observers feel is probable – what impact does that have on the mayor’s re-election bid?

The surprise end to the mayor’s awful Friday came when a state Supreme Court justice, Doris Ling-Cohan, ruled that the state law that prevents gay couples from marrying was unconstitutional. Because the action was brought against the New York city clerk, the ruling created a political nightmare for the mayor – a dramatic example of just how the entrance of a serious Republican primary challenger alters the dynamics of the 2005 campaign.

If the former councilman, Thomas Ognibene, were not attempting to deny the Republican line to the mayor, Mr. Bloomberg could afford not to appeal Judge Ling-Cohan’s ruling. That would delight liberals, and traditionalists would have nowhere to go – all of the mayor’s Democratic challengers support gay marriage. But the ruling affords Mr. Ognibene the perfect issue to energize GOP voters against Mr. Bloomberg.

So the mayor tried to take the middle ground on an issue where there is no middle ground. He declared his personal support for gay marriage while challenging the ruling legally. That did not sit well with Mr. Ognibene, who accused the mayor of trying to have it both ways. Nor did it satisfy the gay groups he has long courted, who vigorously booed the mayor at two events that unfortunately were previously scheduled. That is exactly the kind of ideological bind that the left-leaning mayor had hoped to avoid, the final misfortune on his forgettable, regrettable “Black Friday.”