“Sometimes party loyalty asks too much,” President John F. Kennedy once said. 

New Yorkers know what he meant because they are bearing the brunt of one of those times. 

There can be no honest doubt that President Biden is responsible for the open southern border and the migrant crisis convulsing the nation.

More than 6 million people have crossed during his short tenure, a total dwarfing that of any previous president. 

Day after day, month after month, people stream in from across the globe in record-setting numbers.

The Border Patrol said it arrested 16,500 people over just two recent days, and that doesn’t include the illegal crossers who got away. 

Tens of thousands of others are moving north through Mexico and more caravans and jammed freight trains are behind them. 

The city estimates that nearly 120,000 of the newcomers are in the five boroughs, most on asylum claims, leading Gov. Hochul and Mayor Adams to complain about the cost and logistics.

But both are Democrats, and when they had a perfect opportunity to make common cause with a governor of another state suffering even greater problems than New York, they suddenly defended Biden. 

The reason is obvious: The other governor, Greg Abbott of Texas, is a Republican, making this a perfect example of JFK’s warning. 

In this case, the interests of the people of New York took a back seat to partisanship. 

If Abbott were a Dem, Hochul and Adams would have joined him in a unified approach to solve a shared problem.

But they looked at him only as a member of the other party and chose to defend a policy and a president harming New York. 

Adams once said the migrant surge “will destroy New York City” but then sides with the man responsible for that destruction. 

When he was elected, Adams promised to be the new face of the Democratic Party and show America how to run a city. 

What happened to that guy? 

The reaction was especially disappointing given that both Hochul and Adams lately have been more direct in their criticism of Biden for not helping.

But agreeing with a Republican was a bridge too far, and so they retreated behind party lines. 

Shame on them for turning a blue state into a stupid state. 

Leading New York requires a vision far larger than mere party allegiance, a fact that successful mayors and governors of both parties have always understood. 

Abbott was in town for a Manhattan Institute event and actually complimented Hochul and Adams for demanding that Biden pony up more cash.

But his emphasis was on how both New York and Texas would benefit if the president did his job. 

“Joe Biden can flip that switch any day and stop New York dealing with the consequences of an open border. Until that is done, New York and other states are going to continue to deal with this,” Abbott said. 

That’s a fact, but the reactions were disheartening and disingenuous. 

Hochul was the first to blast Abbott, saying, “They [Republicans] are so hypocritical to come here and tell New York how to deal with a crisis that can be resolved if the Republicans . . . can pull together a coalition of people who actually will solve this.” 

Adams later sang from the same playbook. 

“If he genuinely wanted to be part of the solution to this humanitarian crisis, Governor Abbott would urge his Republican colleagues in Congress to collaborate with President Biden on desperately needed and long overdue immigration reform, instead of using this issue to gain cheap political points,” an aide said. 

Both statements sound as if they were written by the White House, and probably were.

The idea that Republicans hold the key to the crisis is fundamentally dishonest but it’s become a Democratic talking point because Biden refuses to secure the border. 

Except for the expiration of the provision giving him the authority to turn away crossers during the COVID emergency — a provision Biden wanted to eliminate anyway — the laws haven’t significantly changed since he took office. 

What has changed is that Biden was determined to undo nearly everything Donald Trump did, and the border disaster is a direct result. 

The number of people coming across and claiming asylum increased dramatically almost immediately because he promised he would be more welcoming than Trump. 

The migrants took him at his word and many told reporters they came because Biden invited them.

Coyotes and cartels are magnifying that message to reap millions while creating misery and death, something Biden should have thought of before opening his mouth — and the nation’s doors. 

Remember his head fake that Vice President Kamala Harris would work with Central American governments to find the “root causes” of mass migration?

How’s that going? 

Because of Texas’ long border with Mexico, Abbott early on sounded the alarm.

Getting zero response from Washington, he reasonably concluded he needed a bipartisan approach to get Biden’s attention. 

Thus was born his plan to bus migrants to New York and other Dem-led cities, including Chicago and Washington, DC. 

About 13% of the migrants in New York arrived on Abbott’s buses, and his office says they all wanted to come here. 

Unfortunately, Adams is quick to play the race card, and accused Abbott of sending the migrants only to black-run cities.

Which was silly for several reasons, including that Adams himself worked with the Democratic mayor of El Paso to bring thousands of migrants to New York as he advertised Gotham’s sanctuary status. 

It’s also true that Adams is feuding with Hochul because he wants her to force the suburbs to take some of the migrants off his hands.

She refuses because she knows the idea is so unpopular it would end her career. 

After mishandling the problem for more than a year, Adams recently got serious about challenging in court the city’s unique obligation to provide shelter for all comers.

Yet still he and Hochul send mixed messages by urging the feds to expedite work authorization papers for the migrants here, which foolishly adds to New York’s appeal and helps erase the line between legal and illegal immigration. 

In short, the problems and costs will continue to grow worse.

And Democrats, in Washington, Albany and City Hall, are responsible.

Reader Howard Siegel pans the GOP face-offs as amateur hour, writing: “A Republican debate without Donald Trump is like ‘The Producers’ using Ryan Seacrest instead of Nathan Lane to play Max Bialystock.”

The Senate dress code fuss gives reader Keith Linton an idea. He writes: “I watch golf and auto racing and believe government officials should also display ‘sponsorships’ on their clothing. This would include lobbyists, donors, corporations, dark money, governments outside the US, etc.” 

“In sports, more sponsors means more income. That could explain why a legislator can retire as a millionaire in just a few years. Let’s make the sponsors visible!”