Forget about Tom Mulcair, the leaderless Liberals, or even the rantings of Elizabeth May: during this session of parliament, Kevin Page, the parliamentary budget officer, has been the most effective opposition to the Harper government.
The PBO's mandate is to provide Parliamentarians with independent financial analysis of government policies and spending.
Over the past several months, however, Page has been at odds with the Conservatives, as well as various federal departments and agencies, over what he says has been their unwillingness to provide him with complete financial and economic data.
Most recently, Page has been requesting information about the number of public service employees who will lose their jobs and which government programs will be eliminated under the Conservatives' fiscal plan for 2012.
The tension heated up Monday, when Page published a legal opinion he had sought, which states that more than 60 departments and agencies are breaking the law by keeping information from him.
Page landed several verbal salvos against the Conservatives during the F-35 procurement controversy, as well. He accused bureaucrats of keeping information from Parliament and even said that he believed the government purposely withheld information so Canadians would not know the full cost of the aircraft.
He's also raised red flags about Ottawa's crime agenda and its plan to raise the OAS eligibility age.
On Tuesday, the Tories finally lashed out at Page, accusing him of overstepping his bounds in doing his job.
"I have to say with great respect, I believe that from time to time and on occasion the Parliamentary Budget Office has overstepped its mandate," Foreign Affairs Minister John Baird said in the House.
Ironically, the PBO is the brainchild of Stephen Harper.
As a means to forward his 'transparent government' plank of the 2006 federal election campaign, the prime minister promised an office that would provide an accurate and impartial accounting of federal finances, as the Congressional Budget Office does in the United States.
Many Conservatives would now privately tell you, however, they've created a monster.