US Vice-President Dick Cheney has launched a vitriolic attack on politicians accusing the White House of misusing intelligence to invade Iraq.
Cheney has been on the receiving end of much criticism over Iraq
Opposition Democrats were guilty of spreading "cynical and pernicious falsehoods", he said.
As a principal architect of the war, the vice-president has come in for a good deal of personal criticism.
The Democrats' John Kerry later said it was hard to name a Bush official with "less credibility on Iraq".
Another senior Democrat, Senior Harry Reid, dismissed the vice-president's "tired rhetoric".
"Political attacks do nothing to get the job done in Iraq," he said.
'No sitting back'
Mr Cheney resorted to language far stronger than any used before by the Bush administration, the BBC's Justin Webb reports.
The vice-president called the Democrats "opportunists" who were peddling "cynical and pernicious falsehoods" to gain political advantage while US soldiers died in Iraq.
"The president and I cannot prevent certain politicians from losing their memory or their backbone - but we're not going to sit by and let them rewrite history," he said.
A claim that the administration had misled Americans before the war - was one of the most dishonest and reprehensible charges ever aired in Washington, the vice-president continued.
Nobody will be surprised that he is fighting back after rumours he has lost the trust of the president and might be forced to resign but the tone of his comments caused some raised eyebrows within minutes of their delivery at a Washington dinner, our correspondent adds.
President Bush last week suggested politicians were making "false charges" about the reasons for going to war.
Amid new questions in Congress about the intelligence used to justify the invasion, he said it was "irresponsible to rewrite history".