All's well that ends well, so perhaps Philadelphians should simply applaud the news that a stumbling block to plans for a new youth detention center in West Philadelphia has been removed.

City Councilwoman Jannie L. Blackwell has finally given in to reason, but not without getting a little something-something in return for her district.

Now, the entire city's best interests can be served by moving from the current Youth Study Center site off the Benjamin Franklin Parkway under a deal announced Thursday.

The new detention center will be built at 48th Street and Haverford Avenue, likely following its temporary move to the old, state-owned Eastern Pennsylvania Psychiatric Institute in East Falls.

It's a big win on several fronts.

The move will rescue juvenile detainees - and the social-work staffers who supervise them - from an overcrowded and decrepit facility. State welfare inspectors have catalogued some fairly disgusting sanitary conditions, along with evidence of disrepair. While city officials say they've addressed those concerns, no amount of retrofitting can bring this aged facility up to date.

The move also paves the way for an exciting development on the city's cultural and tourism landscape: Once the old Youth Study Center is torn down, the new Barnes Foundation museum will rise on the site - showcasing the stunning art collection scheduled to move from the Barnes' home in Lower Merion.

Those were win-win reasons to find a new home for the detention center, but Blackwell used her informal veto over any city-approved project in her district to delay it three years.

At first, Blackwell's objections appeared to stem mostly from a chilly relationship with Mayor Street. (Maybe she caught him when he

wasn't

"having a great day," as the mayor says.)

Only in recent months has Blackwell been more specific about what she wanted in return for her compliance, including a community center named after her late husband, U.S. Rep. Lucien E. Blackwell, to be part of a new high school whose focus will be criminal-justice education.

If politics is the art of the possible, then officials in the Street administration, the Philadelphia school district and Harrisburg made the right decision in stepping up with the $12 million needed for Blackwell's projects.

By doing so, they sealed an important deal. But the detention center - a major project with citywide import - could have been built by now but for Blackwell's insistence on horse trading as usual.