Recent months have seen the flow of unwelcome undercurrents impeding the good momentum in China-US ties, with Washington labeling unwarranted charges against China over a number of issues. This has raised concerns on both sides. And whether or not the United States Congress approves the renewal of the China-US pact on civil nuclear cooperation will serve as a barometer to gauge the political relations between the two big powers.

On April 21, US President Barack Obama submitted a proposal to the US Congress on continuing the cooperation with China in the peaceful use of nuclear energy. Known as the 123 Agreement under the US Atomic Energy Act of 1954, the pact was signed in 1985 and expires at the end of this year.

The 30-year-old agreement permits transfer of material, equipment (including reactors), components, information and technology for nuclear research and generation of nuclear power. It would provide "a comprehensive framework for peaceful nuclear cooperation with China based on a mutual commitment to nuclear nonproliferation," Obama said.