WASHINGTON — MJ Hegar, candidate for U.S. Senate and mother of two young kids, has asked the Federal Election Commission for approval to spend campaign donations on child care as she seeks to oust Sen. John Cornyn.

"The time and travel demands of federal candidacy place a unique burden on the parents of young children," she told the commission.

Cornyn weighed in Friday with the commission — offering his "full support."

Hegar is the most prominent Democrat hoping to deprive the Texas Republican of a fourth term.

An Air Force helicopter pilot and veteran of combat in Afghanistan, she fell just short of ousting U.S. Rep. John Carter in a district north of Austin, drawing national attention with a high-octane campaign ad that went viral.

Federal law bars diversion of campaign cash to "personal use." Donor funds can't be spent on groceries or a home mortgage. But the Federal Election Commission has long held that candidates may tap campaign accounts for outlays they wouldn't need to make if they weren't running for office.

In 1975, the commission let a candidate pay for child care out of campaign funds when his wife joined him on the stump.

Last year, the agency gave its blessing to Liuba Grechen Shirley, a New York Democrat who'd been caring for her children full time as she worked from home as a consultant. She gave up that work to run for Congress and was paying a babysitter $22 an hour. She lost to Rep. Peter King, who said at the time that he was fine with whatever the commission said on the matter.

Hegar's lawyers filed a request June 5 for an advisory opinion tailored to her situation.

Unlike Grechen Shirley, she and her husband were already paying for full-time day care. Through her lawyers, Hegar told the commission that after announcing her Senate candidacy, she left her job as an author and public speaker "to devote her full time to her campaign."

Until then, she and her husband had worked full time.

"In prior Advisory Opinions, the Commission has recognized that campaigning for federal office can cause unique problems for candidates with young children," her letter said.

Federal regulations allow candidates to draw a salary from their campaign accounts once the filing period opens for the office they are seeking. That window opens in December, and by noting that restriction, Hegar's letter suggests she may end up doing so.

Hegar, 43, lives in Round Rock. She raised $5.1 million for last year's House bid. She launched her Senate bid on April 23. Her first three-month campaign finance report is due in mid-July.

Cornyn, 67, has two grown daughters and had $7.4 million in his campaign account at the end of March.

Read Cornyn's letter here. Hegar's letter is below.