US criticised UPA chairperson Sonia Gandhi's failure to overcome the Left's opposition to the nuclear deal, according to a leaked American diplomatic cable which was sent in November 2007.
"With the future of Indian foreign credibility hanging in balance, Sonia Gandhi has been unable to show principled leadership even when it might benefit her party at the polls. Mrs Gandhi never misses an opportunity to miss an opportunity," the Guardian newspaper quoted of the cables.
The communists are also spoken of harshly by the US diplomats.
Prakash Karat, the Communist party of India (Marxist) general secretary, is described as an "extortionist".