Clinton's brief stop in Pyongyang made him the highest-level US visitor since President Carter in 1994. That was a propaganda coup for North Korean leader Kim Jong-Il, who is in poor health and trying to ensure his succession, according to experts on the secretive regime.
Mr. Kim spiked tensions in the region when he conducted a nuclear test in May and unleashed subsequent missile launches.
Playing into Kim Jong-il's hands?
Some critics in South Korea, which is wary of a US diplomatic end-run around it, have sniped at Clinton for playing into Mr. Kim's hands. In an editorial, conservative daily Joong Ang warned that the US and other nations must "avoid the mistakes of the past, when they blindly pursed dialog and ended up falling right into the hands of the North."
He says China is also wary of being "marginalized" by any bilateral track between the US and North Korea, particularly at a time when it is being pressed to apply stricter UN sanctions to North Korea.
In an editorial, China's state-owned Global Times welcomed Clinton's visit, but cautioned that the diplomatic goal must be the revival of six-party peace talks.
"That goal can only be realized if the US and North Korea make sincere, substantial efforts," it said.