Bush's support is mostly a formality at this point; Romney is the presumptive Republican Party nominee. Ron Paul, the only other candidate not to formally suspend his bid, said Monday he would no longer be on the campaign trail. Bush's parents, former President George H.W. Bush and first lady Barbara Bush, also have endorsed Romney.

But Romney's campaign notably did nothing to commemorate the endorsement. Unlike with George H.W. Bush, whose endorsement was widely heralded by the campaign, no press release or announcement was made about the nod from the last Republican to occupy the Oval Office.

That speaks to the lingering optics issues for Republicans from the Bush administration — the former president continues to receive the lion's share of blame from voters for the poor economy and critical marks for his handling of the war in Iraq.

President Obama has repeatedly referenced the Bush administration while campaigning against conservative economic principles.

“We tried this for eight years before I took office — we tried it,” Obama said to a crowd at a Florida college last month. “It’s not like we didn’t try it.”

But it's possible Bush's endorsement could boost fundraising among party loyalists. Democrats have leaned on former President Clinton throughout the campaign, with the former commander in chief appearing in ads and at high-profile fundraisers.