Experts and lawmakers alike agree that Treasury Secretary Timothy Geithner has the power to adjust how much is withheld from paychecks for tax purposes — for all taxpayers or just for some.

By doing so, Geithner could ensure paychecks reflect the White House position that wealthier taxpayers with annual income higher than $250,000 see their taxes rise. Geithner at the same time could leave withholding tables where they are for the middle class, ensuring those workers don’t see a higher cut from their paychecks…

The tactic could buy Washington precious time to strike a tax agreement without pinching the economy, but it carries substantial risk. If the administration miscalculates where rates end up, tinkering with withholding could morph tax refunds into hefty bills.