Richard Nixon learned this the hard way. He likely would have kept his job as U.S. president in 1974 had he not tried to cover up Republican participation in the Watergate burglary.
The Harper government likely knows this as it tries to ward off the effects of parliamentary testimony by diplomat Richard Colvin. This is why its damage control strategy is risky.
Colvin testified before MPs last week that he tried repeatedly to warn his superiors that detainees the Canadian military turned over to Afghan authorities were virtually certain to be tortured. Colvin says his superiors were indifferent at best and went as far as telling him to keep quiet and not put anything in writing.
Defence Minister Peter McKay has been since attacking Colvin's testimony as not credible. In fact, he went as far as hinting that Colvin was playing into the hands of the Taliban.
But the government's strategy seems to be unraveling quickly. The minister has had to acknowledge Canada has stopped transfers of detainees to Afghan authorities at least four times because of suspicions. Groups like the Red Cross, and even a former diplomat from the European Union, have stepped forward to back up Colvin's testimony.
Even the Afghanistan Independent Human Rights Commission,which is partially funded by Ottawa, has said in a published report detainees have been tortured.
It is interesting to note that the government has yet to produce any evidence to contradict Colvin's testimony. Nor has it actually denied that torture has taken place. Instead it has been concentrating its energy on discrediting Colvin as a witness.
This is how the Harper government likes to deal with embarrassing topics -- shoot the whistleblower.
It fired Linda Keen as president of the Canadian Nuclear Safety Commission in December 2007 because she insisted on keeping the Chalk River nuclear reactor closed for safety concerns. As things have turned out, her concerns were well founded.
The government dealt with allegations that it offered money while in Opposition to the late MP, Chuck Cadman, to induce him to support the Conservatives in voting down the Liberal government in 2005 by attacking the reporter who broke the story. The Tories accused Tom Zytaruk of doctoring interview tapes.
An expert would later conclude those tapes were never tampered with. However, the Tories were successful in muddying the narrative of its critics until the Cadman story died.
Will it work this time? It just might because of public indifference about the fate of Afghan detainees.
Published reports of torture of Afghan detainees have been surfacing since February 2008. But the Canadian public has hardly been outraged.
For this controversy to continue to have legs, the Opposition is going to have to demonstrate to the public that innocent Afghan citizens have been detained and tortured in the same net as Taliban fighters because of Ottawa's negligence.
It also is going to have to show the general public that Canada's military mission has been hurt because of torture of innocent detainees has caused distrust among the Afghan people.
If the Opposition can make those two points clear in the public mind, the government will likely have to call a judicial inquiry, and accept some top resignations. But so far the Opposition has not been able to do that.
Of course, even if the government succeeds in warding off this controversy as it did with the Cadman affair, it will do so with considerable damage to its credibility at a time when Canadians have started to feel more comfortable with the Tories.
I look forward to your comments.