In elections as in high school, seniors hold a lot of clout. And in South Carolina’s First Congressional District, where one in four residents is over the age of 55, they could decide the outcome of the May 7 election for Tim Scott’s vacated House seat.

So what’s important to senior citizens? According to a voter guide that AARP South Carolina distributed to its 110,000 members in District 1, three big issues on the line are protecting and strengthening Social Security, putting Medicare on “stronger financial ground,” and helping people save for retirement. The AARP (formerly the American Association of Retired Persons) doesn’t endorse candidates, but it does provide a rundown of where the two major-party candidates stand on the issues.

Republican candidate Mark Sanford says in his platform that he wants to “modernize” Social Security and Medicare and enact “entitlement reform” to stop mounting costs. During his previous stint in the District 1 seat, Sanford helped lead a failed charge to privatize Social Security.

Democratic candidate Elizabeth Colbert Busch has said that she does not support proposals to privatize Social Security or Medicare. According to the platform on her campaign website, Colbert Busch says Social Security is safe for at least 20 years and suggests “modest changes” that would start by adjusting Social Security contributions and benefits for the wealthiest Americans.

The AARP won’t weigh in either way on the election, but its leaders did express disappointment after Colbert Busch backed out of a debate the AARP was planning to host on April 17. The only reason her campaign would give was a “scheduling conflict,” although AARP National Engagements Director Pete Jeffries says the Colbert Busch campaign knew about the debate months in advance. “We’re extremely disappointed that the only prime-time televised debate where we knew that these issues were going to be front and center in front of the voters of the First Congressional District, that now that’s a huge missed opportunity,” Jeffries says.

Last week, another group, the left-leaning National Committee to Preserve Social Security & Medicare, announced its endorsement of Colbert Busch, saying in a press release that she would “protect those benefits against any political or corporate interests that would diminish them through harmful cuts or other risky proposals such as privatization.” Max Richtman, president and CEO of the advocacy group, says his group reached out to both candidates and asked them to go through an interview process and fill out a questionnaire, but the Sanford campaign never responded. Richtman says that Colbert Busch “obviously doesn’t have a voting record, but her positions based on interviews and the questionnaire led us to support her.”