As Qaddafi's government comes apart, new concerns for U.S.

While rebels in Libya took over the streets of Tripoli and declared an end to the rule of Muammar el-Qaddafi, major questions quickly need to be answered in the coming hours and days, including what kind of transitional government comes next and whether an international peacekeeping force should be sent into the North African country.

Current and former U.S. government officials expressed concern late Sunday that Libya could tailspin into chaos without a steady transition and quick establishment of new laws.

Key senators who've been the fiercest critics of President Obama's handling of the Libyan conflict argue the U.S. government should immediately step up its assistance to the Transitional National Council in Libya. The council has been preparing to step into power to manage a post-Qaddafi state.

Sens. John McCain, R-Ariz., and Lindsey Graham, R-S.C., called on the Obama administration to "move expeditiously" to release $34 billion in Qaddafi-linked assets the U.S. froze in February to be used for the reconstruction of the country.

"The Libyan people have won their freedom, but now they must build the durable institutions necessary to keep it, including a transparent and inclusive political process, a free and independent media, an impartial system of justice and the rule of law, a free economy, and unified, professionalized security forces that answer to civilian authority," the senators said in a joint statement.

Sen. Joe Lieberman, ID-Conn., who along with McCain and Graham criticized Obama for not being aggressive enough in ordering military operations in Libya, called for the U.S. government to "redouble" its assistance to the transitional council.

"Although I am optimistic that the Libyans will be able to shoulder the bulk of the transition to democracy on their own, I also hope that the U.S. and its allies will make available any and all assistance they request, including a civilian international monitoring mission," Lieberman said.

Lieberman, McCain and Graham all said the Obama administration should help prevent acts of retribution in Libya and initiate a process of national reconciliation, but didn't say how they thought this should occur. There was no immediate mention of U.S. boots on the ground.

U.S. lawmakers like House Intelligence Chairman Mike Rogers, R-Mich., have also been worried about preventing chemical weapons in Libya from falling into the hands of Islamic radicals.

NATO, which helped provided air cover for the rebel assault on Tripoli over the weekend, said it stands ready to work with the Libyan people and the Transitional National Council. NATO Secretary General Anders Fogh Rasmussen said the transition "must come peacefully."

"They [the TNC] must make sure that the transition is smooth and inclusive, that the country stays united, and that the future is founded on reconciliation and respect for human rights," he said in a statement.

But John Bolton, former U.S. ambassador to the United Nations, told Fox News late Sunday that the United States and its allies may not have done enough over the past five months to prepare for the fall of Qaddafi. He noted that Libya does not appear to have a stable military _ something that was instrumental in helping neighboring Egypt manage its civil uprising.

The three senators also said developments in Libya should send a message to other regimes in the Middle East, especially that of Syrian President Bashar al-Assad. "In particular, that is a lesson for Bashar al-Assad, and we are confident that his regime will soon join Qaddafi's on the ash heap of history," McCain and Graham said.