Heidi Cruz, a Harvard Business School graduate and former Bush administration official, has emerged as a central figure in her husband’s campaign, charming on-the-fence donors while acting as a bridge to the Republican establishment.

The effort to broaden Ted Cruz’s appeal is crucial as he soars in the polls. He has long had a strong base of support among conservative Republican activists, but he has alienated moderates and the party’s senior leadership, partly because of his penchant for confrontation, including leading an effort to shut down the government in 2013.

Whatever people may think of her husband, Heidi Cruz tells potential donors and supporters, he is a man of his word, cool under pressure and won’t shy from a fight to implement the free market principles they believe in. Several donors interviewed say her pitch has helped to win them over.

While it is not unusual for spouses to serve as character witnesses, what sets Heidi Cruz apart is her role as a bridge to the Republican establishment and the zeal she brings to it. Many political spouses, including fellow Republican candidate Jeb Bush’s wife, Columba, and President Barack Obama’s wife, Michelle, engage in politics only reluctantly.

But Cruz, on leave from her job as a Goldman Sachs executive in Houston, has immersed herself in the 2016 presidential race. She not only woos donors but takes part in strategy sessions, bringing her business savvy to the effort to keep the campaign’s budget as lean as possible.

In visits to states like Virginia and North Carolina, Heidi Cruz tries to soften her husband’s hard-edged image. She regales supporters with stories about the flowers he brings her on Valentine’s Day and his adherence – despite a hectic campaign schedule – to the couple’s Sunday date nights. Cruz met her husband on George W. Bush’s presidential campaign in 2000.