Mayor Nutter came up with the perfect reference to make his case that the city must do more for the homeless.

"A tale of two cities" is how the mayor described a small park where the homeless congregate in comparison to the luxurious Four Seasons Hotel, which sits on the opposite side of Benjamin Franklin Parkway and 18th Street.

There is something desperately wrong with that picture. It warrants a serious commitment by the city to change the situation.

Nutter wants to do just that with an $8.3 million plan unveiled last week that commits the city and the Philadelphia Housing Authority to provide 700 housing units and beds for the homeless.

That won't meet the total need, nor will it address every homeless issue in the city, but it is a long-overdue, positive step toward getting more of the destitute off city streets and making their welfare a higher priority.

Advocates for the homeless estimate that at least 400 people were living on Philadelphia's streets this spring. That number will likely increase during the summer months. Ten times as many - about 4,000 people - were living in city and private shelters last summer. Advocates say that number, too, is rising.

Nutter's plan would provide support services for those placed in PHA units and add a limited number of residential beds for substance-abuse and mental-health treatment. Advocates say social- service and support programs must play an integral part in any effective effort to help the homeless get back on their feet.

More housing units and beds would serve the street population as well as destitute families, who account for more than half of the city's homeless population.

The plan calls for PHA to earmark 500 of its housing units for the homeless - 300 for families and 200 for individuals. That means bumping them ahead of 48,000 people on the waiting list for PHA housing. But that's understandable in that the city should give priority to those in the most dire circumstances.

The plan calls for the city to provide an additional 200 housing units and beds over a three-year period. But that's beginning in 2010, which seems too long to wait for those who need housing now. The city should try to find a way to make that happen sooner.

The city also plans to fund 50 "safe-haven" beds in residential-treatment facilities, and an additional 25 beds to be used either as safe-haven beds or as supportive housing. Two overnight "cafes," special drop-in centers that offer food and aid for the homeless, will also be continued.

Existing state and federal funding will be used to pay for the new homeless plan. That's good news for the city treasury.

Only four months into his term, Nutter deserves praise for moving quickly to come up with a plan to battle homelessness. He is correct in calling it "one of the most serious crises the city faces."