Lt. Gov. Anthony G. Brown stepped into the role of surrogate for President Obama Monday as he joined in a conference call to denounce former Massachusetts Gov. Mitt Romney's record on veterans' issues, the federal budget and the GOP presidential candidate's charge this weekend that Obama doesn't believe in "American exceptionalism."

Brown, a veteran of the Iraq war, charged that Romney was "out of touch with reality" and "went over the line" with his criticism of Obama. The lieutenant governor pointed to Obama's debut on the national stage in 2004 as a speech that was all about American exceptionalism.

During a call sponsored by the Truman National Security Project, Brown scorned Romney's endorsement fo Wisconsin Republican U.S. Rep. Paul Ryan's budget plan, charging that the spending plan fails to even mention veterans. Brown charged that as governor Romney proposed eliminating hiring preferences for veterans and as a presidential candidate back the conversion of Veterans Administration hospitals into a voucher program.

By contrast, Brown said, Obama has "kept his promise to veterans and has been steadfast in his support."

Striking what will be a common theme for Democrats through the November election, Brown charged that "the Romney-Ryan budget would turn Medicare into a voucher program."

During an appearance over the weekend in Wisconsin, Romney charged that  “our president doesn’t have the same feelings about American exceptionalism that we do.”

 “I think over the last three or four years, some people around the world have begun to question that," he added.

Brown's comments came on the even of the Maryland primary, in which Romney is expected to trounce his Republican rivals and move closer to the Republican nomination.