Advisers to Jeb Bush in this crucial early primary state have asked national campaign officials in recent weeks to send in George Bush, 69, who so far has appeared only at private fund-raisers, to vouch for his younger brother on the campaign trail.

The request for reinforcement underlines the growing urgency that backers of Jeb Bush, the former Florida governor, feel as other candidates vault ahead of him by stirring the passions of the party’s base…

What is more, given the former president’s unpopularity among many in the broader electorate, joint appearances by the brothers could provide irresistible footage for Democratic attacks against Jeb Bush if he wins the Republican nomination. The continued instability in the Middle East, in particular, could remind voters of George Bush’s decision to invade Iraq and make joint images of the Bush brothers potent fodder for the opposition.

“It may ruin the race for him down the line, but it could win the race here,” said Katon Dawson, a former chairman of the South Carolina Republican Party.