Why believe either the Cons or Grits?

Two years ago Stephen Harper was adamant that Canada should send troops to Iraq.
Now he says he would not.

Prime Minister Martin claims to be pro-health care, but his government has failed to restore full transfer payments to the provinces, so they can restore health care to its pre-Mulroney well being.

These are just two examples of double speak from our politicians.

My question is: Why should we believe anything these people have to say?