Updated with comments from the press conference, reactions.

St. Louis, St. Louis County and about a dozen social service agencies plan to seek federal money to provide temporary shelter and care to some of the thousands of unaccompanied minors from Central America crossing the southern border of the United States.

"It’s the right thing to do. That’s the easy answer," said Mayor Francis Slay, who started the effort to bring the coalition together. "This is really about showing compassion for young people who have no place else to go, and they’ve come here for help."

Slay was joined at a City Hall press conference by county executive Charlie Dooley and representatives from the various social service agencies in the coalition.

"We have always cared about people," Dooley said. "We will always find ourselves doing what is right, regardless of the politics. It's not about the politics. It's a humanitarian effort."

The number of children illegally crossing alone into the United States has grown significantly in the last five years, especially those from Honduras, El Salvador and Guatemala. Federal law requires that unless they started their journey in Canada or Mexico, children who are picked up by the Border Patrol must be transferred to the Department of Health and Human Services within 48 hours, rather than be sent back to their country of origin.

That's where the coalition would come in.

The children would be in St. Louis for about 30 days while HHS locates relatives or other adults in the United States to sponsor them while the federal government determines whether they can stay legally in the country. The grant funds would help cover the cost of housing the children, as well as provide physical and mental health care, education and other social services.

"The major issue is trauma," said Rose Crofford, the chief operating officer of Marygrove Children's Home, which will take in some of the children. "They're coming from war-torn countries -- countries with these big drug cartels -- and they've had family members murdered, and seen lots of things in their short lives that most of us won't see in their entire lives."

A Rapid Response

The coalition submitting this grant came together quickly. Suzanne LeLaurin, the senior vice president for programs at the International Institute of St. Louis, said she was approached by Slay's deputy chief of staff July 17, wanting to know what the St. Louis community could do in response to the crisis at the southern border. LeLaurin made him aware of an HHS funding opportunity to provide temporary residential care to the migrant children. The application is due August 5.

"We very quickly identified three residential care facilities who were interested in responding to this crisis and had bed space available," LeLaurin said. The International Institute agreed to administer the grant. A wide coalition of entities, including St. Louis, St. Louis County, the United Way and Casa de Salud, agreed to provide services. The Incarnate Word Foundation is contributing $25,000 to help with any expenses not covered by the federal grant.

"It's such a statement -- when a bunch of people get together for a committed cause -- of what can be done," said Crofford. "I'm kind of getting goose bumps talking about it."

Excess Capacity

The coalition made it a top priority to ensure that no Missouri children would be shut out of needed care by the effort to help migrant children.

"There will be no American children not getting services because of this effort," Slay said. "There won't be any resources used that otherwise would be used for people who are already here."

The pot of money available, coalition members said, is expanding to accommodate the changing needs.

"I understand that some people look at the size of the pie and they assume that it's limited, and that to care for one person means there's another person we don't care for," LeLaurin said. "Every entity that's been approached to be a part of this has expressed a desire to provide care for these children. Even some of the agencies we contacted for residential care who did not have space available said, 'I'm sorry we don't space available, but if there's anything we can do to help, please let us know'."

Some of that excess capacity is at St. Vincent Home for Children in Florissant, where executive director Carla Monroe-Posey said she got enthusiastic approval from her board to join the coalition.

"Our long-term, since 1850, commitment to serving children in need of assistance will certainly be met by this 21st century need," she said.

Managing The Reaction

Slay shrugged off any political ramifications over his decision to get the city involved in a hot-button issue like immigration.

"If there are heartless people who want to criticize what we're doing, so be it," he said. "We're going to do what's right for these kids. I've talked to some of the elected officials in some of the communities where these facilities are located and they're supportive."

Monroe-Posey worked the phones as soon as St. Vincent agreed to participate. She also expects no sizeable reaction to the decision.

"I spent my Wednesday and Thursday calling all our key constituents and, uniformly, they were very supportive and some were absolutely enthusiastic," she said.

Patrick Green, the mayor of Normandy, where St. Vincent is located, and Gerry Welch, the mayor of Webster Groves, both attended the announcement. Great Circle, the third residential home, is in Welch's city. Florissant mayor Tom Schneider was not present and did not return a phone call for comment.

In a written statement, Democratic Congressman William Lacy Clay said he supports and welcomes "all efforts to provide safe refuge to those border children who qualify under the law," and he stands ready to "help our community extend compassion, kindness and shelter to them."

But not everyone supported Slay and Dooley's efforts. On Twitter, Ed Martin, the chairman of the Missouri Republican Party, called Slay the St. Louis Rahm Emanuel, referencing the Chicago mayor's announcement earlier this week that he would aggressively expand the amount of shelter space available in Chicago for the young migrants.

"We've got plenty of people in our communities that need help, need caring, need charity, and the idea that Slay and Dooley are going to grandstand to help Obama is just deeply offensive," Martin said.

Rick Stream, a Republican state representative and candidate for County Council, agreed with Martin.

"While I laud the humanitarian motivation behind it, plans announced by St. Louis officials to house unaccompanied children from south of our border using federal tax dollars causes me grave concern," Stream said in a written statement. "The effort of the St. Louis community to provide care for these children is well-intentioned, but ill-advised. By this action we are enabling the Obama Administration to continue these reckless policies and have encouraged more illegal immigration and unaccompanied children to leave their homes and face potential sexual exploitation and abuse."

Rep. Blaine Luetkemeyer, a Republican whose district includes parts of St. Charles County, issued the following statement:

“As a father and grandfather, it is my belief that we must do all we can to ease the suffering of these children who have arrived at our borders based on this Administration’s failed immigration policies. Congress is capable of helping the thousands of people, including young children, return safely home. While we are a compassionate nation we also are a nation of laws. We must do what is right for the safety of the American people and the well-being of the unfortunate souls lured here.”

Mike O'Mara, the Democratic councilman for the county's 4th Ward, took aim at Dooley for again failing to inform the council about what's going on.

"This is the first I've heard about it," he said when contacted by St. Louis Public Radio. "I have no knowledge of what's going on." He said that his family had personally supported Marygrove for years, but had no reaction about the decision to apply for federal money.

Follow Rachel Lippmann on Twitter: @rlippmann