Budget analysts, including at the conservative Heritage Foundation, have noted that, based on standard economic growth projections, Romney's commitment to spending at least 4 percent of GDP on defense is in effect a promise to spend over $2 trillion more than President Obama is proposing.
Obama has deployed that fact in the debates and in speeches to illustrate that Romney's tax and spending plans amount, in effect, as vows to balloon deficits or raise taxes on the middle class.
Romney campaign officials, including his running mate Paul Ryan, have criticized the $2 trillion figure, without explanation.
But analysts say that even if Romney ramps up the Pentagon's base budget slowly, such that it only reaches 4 percent late into his presidency or even at the end of his second term, Romney's target is still in effect a pledge to spend nearly $2 trillion more than Obama has proposed.
Per Bloomberg: "If Romney achieved his goal of setting defense spending at 4 percent of GDP by 2017, the difference between his 10-year defense plan and Obama's current decade-long plan would be $2.03 trillion, according to a study by Todd Harrison, a defense budget analyst at the Center for Strategic and Budgetary Assessments. If the target is achieved gradually by the end of a second term, the additional expenditure would be about $1.75 trillion, Harrison said in an e-mail. The estimates are in current dollars."