At least 1,300 people have died as rebel forces invaded Tripoli. Another estimated 20,000 have been wounded. Gaddafi's two eldest sons are in custody. President Obama is now calling for Gaddafi to step down. The President has been referring to this as a new age for Libya.
Gaddafi has ruled Libya for 42 years. Ruthless and intolerant of opposition, he also has modernized Libya. Rebel forces (backed by the US and France) decide to overthrow the Libyan government as part of the Arab Spring back in March. This lead to the United States providing air support but the lack of support at home lead to NATO taking over the lead.
So what do we get for all of this? We have yet to hear who will replace Gaddafi. For those who may be too young to remember, the US backed another regime change in Iran resulting in the Shah taking over. This was such a popular decision that the Iranian people, who had grown tired of being tortured and killed by a US puppet, that they stormed the American embassy. The Shah was thrown out and Ayatollah Khoemeni took over setting the stage for a far more belligerent Iran to pursue nuclear weapons.
Gaddafi was no friend of the US but had certainly mellowed since 9/11. Whoever takes over in Libya will be seen as a puppet of the US and Europe. Iraq and Afghanistan are a mess. Iran has become a theocracy with a decided bent towards nuclear weapons. Syria has warned against any outside military intervention as it deals with its post Arab Spring situation.
I just don't see where replacing Gaddafi by backing the rebels was a prudent idea that will produce any strategic gains.