GOP presidential hopeful and former House Speaker Newt Gingrich speaks at the Republican Leadership Conference in New Orleans in June. (AP Photo/Patrick Semansky, File) (Patrick Semansky/AP)

Employees of presidential candidate Newt Gingrich grew increasingly concerned in recent years about their boss’s purchases from luxury jeweler Tiffany & Co., worrying that if he followed through on plans to run for president, it could become a political liability.

The purchases included jewelry valued up to as much as $300,000 for his wife’s Christmas gifts, selected each year during a fall Potomac River cruise sponsored by the jeweler. On a smaller scale, Gingrich (R) spent about $40,000 over four years, buying Tiffany trinkets as holiday gifts for up to 100 employees, according to three former employees who spoke on the condition of anonymity because of the issue’s sensitivity.

The former employees agreed to be interviewed by the The Washington Post to explain how staff concerns mounted about Gingrich’s spending and his relationship with Tiffany. All three said they admire Gingrich but question his judgment.

Politico reported in May that Gingrich and his wife, Callista, maintained a $250,000 to $500,000 personal credit line at Tiffany in 2005 and 2006, which was acknowledged in financial disclosure forms filed by Callista Gingrich, a former congressional staffer.

The Gingrich campaign recently confirmed to The Post that Gingrich maintained a second Tiffany credit line for $1 million, which will be listed on his presidential candidate financial disclosure forms. But a Gingrich spokesman said the former House speaker has no debt with the company.

Gingrich’s Tiffany spending has been questioned by his Republican opponents. He has offered few details about his relationship with the jeweler or the purchases made.

Joe DeSantis, Gingrich’s campaign communication director, declined to address the details offered by the former employees and dismissed their accounts as trivial.

“Class warfare does not create jobs,” he said in a written statement. “Newt’s Jobs and Prosperity Plan will.”

The former employees said Gingrich’s gift-giving, at first, was regarded as a sign of generosity. At annual Christmas dinners for staff, small Tiffany boxes wrapped in white ribbon were left at each place setting, each containing items costing about $100 or more.

The Gingriches were generous to staff in other ways, typically contributing up to 20 percent of each staff member’s salary to his pension fund and giving a minimum year-end bonus of 20 percent of base salary, and often much more.

“The Gingriches have always been extremely generous with their staff,” said former campaign spokesman Rick Tyler. “. . . I think those gifts were always appreciated.”

Gingrich’s spending on jewelry for his wife came to staff members’ attention through a 2004 article in Roll Call. A short item noted that he purchased a $300,000 piece of diamond jewelry while they were among 20 or 30 other Tiffany customers on the annual Potomac cruise. In the article, a Gingrich spokesman declined to confirm the price because of “security concerns.”

The former employees said the Tiffany cruises became an yearly outing during which the couple chose Callista’s Christmas presents.

The extravagant appearance of the purchases also generated concern among employees in 2008, when some companies run by Gingrich encountered financial difficulties. Over the next two years, bonuses and pension contributions were reduced or eliminated. Even though the Gingriches were using personal funds for the Tiffany items, the disparity made some employees uncomfortable.Gingrich’s network of entities included Gingrich Communications, which helped promote the Gingrich brand by marketing his books and speaking engagements; Gingrich Productions, a movie-production company led by his wife; and the Center for Health Transformation, a membership group for corporate health-care clients to work together on health-care solutions.

Sixteen Gingrich campaign staff members resigned June 9 , claiming that Gingrich was allowing his wife to dictate the terms of his campaign schedule. The disagreement between staff members and the candidate came to a head when Gingrich insisted he would go on a Greek cruise that his wife had been planning for the couple.