Who's dealing with the border crisis as Washington clears out?

When Congress left town on Friday for their five-week summer recess without sending President Obama a bill to deal with the flood of undocumented immigrants crossing the U.S-Mexico border, they abandoned him with a crisis in dire need of a solution.

So now it's up to Mr. Obama, who's leaving for his own two-week trip to Martha's Vineyard this weekend, to find a way to manage it.

"I'm going to have to act alone because we don't have enough resources," the president said Friday.

In the short-term that means juggling budgets within the Departments of Homeland Security (DHS) and the Health and Human Services (HHS), the two agencies that play the biggest role in the crises, to make ends meet. The principal enforcement agencies within DHS, Immigration and Customs Enforcement (ICE) and Customs and Border Protection (CBP) are scheduled to run out of funds in mid-August and mid-September, respectively.

Thad Bingel, a former chief of staff at CBP who now works at Command Consulting Group, told CBS News that ICE and CBP will "raid every other pot of money that they have for the next two months...in order to keep removal operations and the shelter operations going."

There may be leftover money from department purchases that weren't made, overtime that wasn't used, or additional receipts from user fees. The Federal Emergency Management Agency (FEMA), a part of DHS that is helping manage the child-immigrant crisis, could have disaster funds that were allocated to them but never spent. They could also dip into funds allotted for long-term projects that haven't been spent yet, but that would require Congress to refill those coffers next time they are handing out money to the federal agencies.

A "less preferable option," Bingel said, would be for ICE and CBP to spend money they don't have and get Congress to make up the difference next fiscal year. "That of course gets you into all sorts of trouble" he said, and could mean a nasty fight between the administration and Congress.

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But Jayson Ahern, a former acting and deputy commissioner of CBP who now works at the Chertoff Group, warned that the agencies may not have that much money left over so close to the end of the fiscal year - especially with budgets already leaner than usual because of the lower levels of spending mandated by sequestration.

"They're already at a very lean level and thinking they can absorb these types of cuts or other impacts to the budgets -- I don't think its fair," Ahern told CBS News.

Certainly one of the worst-case scenarios would be for CBP to begin pulling back from its operations to protect the border and manage the influx of children because they didn't have the money to pay for it.

"It would just set back the positive improvements that have already been made," Ahern said.

Bingel said it was an unlikely scenario, and one that would almost certainly be used to make a political point.

"If the agencies do that it's at the direction from on high and it's at the level of political gamesmanship," he said.

House Speaker John Boehner, R-Ohio, had initially said the president could tackle the border crisis alone when it appeared Republicans could not rally around a single funding bill (they ultimately passed a bill that was a dead-end with the Democrat-led Senate and the White House on Friday). The list of possible actions Boehner offered ranged from "send the strong, public message that those who enter illegally will be returned" to "stop abusing his prosecutorial discretion authority," a reference to the justification the president has used for executive actions such as Deferred Action for Childhood Arrivals (DACA) which shields certain immigrants brought to the U.S. illegally as children from being deported.

But Mr. Obama appears prepared to move in exactly the opposite direction.

"Because of Congress's failure to fix the immigration system and to pass the supplemental appropriations, we need to deal with the specific crisis on the border... the president has no choice but to act," White House senior adviser Dan Pfeiffer said on ABC's "This Week" Sunday.

Pfeiffer pushed back on reports that the president is considering expanding the DACA program to the parents of those children in a way that could end the prospect of deportation for as many as 4.4 million immigrants living in the U.S. illegally. He said Mr. Obama is still waiting on a review of the nation's deportation policies and recommendations from the attorney general and DHS secretary for ways to redirect resources from the country's interior down to the border.

But Pfeiffer said the president "is going to do what he can...under the confines of the law" by the end of summer.

Any unilateral action is sure to spur even more anger from House Republicans, who have already voted to move forward with a lawsuit that charges the president with exceeding his executive authority. It could also re-ignite suggestions of impeachment being tossed around by some Republicans (and used successfully for fundraising by Democrats).

"None of us want to do the thing that's left for us as an alternative, but if the president has decided that he simply is not going to enforce any immigration law or at least not against anybody except the felons which essentially he has done already...I think Congress has to sit down and have a serious look at the rest of this Constitution and that includes that "I" word [impeachment] that we don't want to say," Rep. Steve King, R-Iowa, said on "Fox News Sunday." "Where would we draw the line otherwise if that's not enough to bring that about then I don't know what would be."

King was among the House Republicans who pushed the House to vote on a bill that would bar Mr. Obama from continuing or expanding DACA Friday night, in anticipation of unilateral action while Congress is gone.

In a separate interview on Fox, Sen. Marco Rubio, R-Fla., one of the original authors of the comprehensive, bipartisan Senate immigration overhaul that passed last summer, said that executive action from the president would be "one step forward but three steps back."

"It would further drive this narrative that this is a president not interested in enforcing our laws, which right now is the single greatest single impediment to moving forward," Rubio said.

He suggested that the best way to overhaul the immigration system going forward would be to secure the border, modernize legal immigration laws in a way that makes the system reward merit more than family, and then "address in a reasonable yet responsible way" the millions of people living in the U.S. illegally.

The only way that might happen is if Republicans capture the Senate in the November midterm elections and feel like they don't have to compromise with Democrats to get a bill out of Congress. And that still may not be enough. Boehner has insisted time and time again that his members simply don't trust the president to enforce any immigration laws Congress might pass.