Dear Jim Lehrer,
Are you aware of the following history?
In February 2008, John McCain voted against a bill that would supposedly have banned torture, and then applauded Bush for vetoing the bill.
In 2005 John McCain championed the McCain Detainee Amendment to the Defense Appropriations bill for 2005, which passed the Congress and was signed into law by Bush, adding one more redundant ban on torture to existing U.S. law, despite Vice President Cheney having lobbied hard against it. But McCain allowed a major loophole for the CIA and then kept quiet when Bush threw out the whole thing with a "signing statement." Bush and Cheney's administration continued to torture without any apparent slow-down or alteration in actual policy whatsoever.
In 1994 the United States ratified the Convention Against Torture and Other Cruel Inhuman or Degrading Treatment or Punishment (CAT), requiring that the United States work to prevent all forms of torture.
In 1992 the United States ratified the International Covenant on Civil and Political Rights (ICCPR), banning torture or cruel, inhuman or degrading treatment or punishment.
In 1968 John McCain was tortured.
In 1949 the United States ratified the Geneva Convention relative to the Treatment of Prisoners of War, banning violence to life and person, in particular murder of all kinds, mutilation, cruel treatment and torture, as well as outrages upon personal dignity, in particular, humiliating and degrading treatment.
In 1948 the United States ratified the Universal Declaration of Human Rights banning torture or cruel, inhuman or degrading treatment or punishment.
In 1788 the United states ratified the Constitution, ordaining that all treaties made under the authority of the United States shall be the supreme law of the land.
So, why, Mr. Lehrer, could you not ask Senator McCain this question: