Last week the president continued his ongoing feud with the National Football League.

CBS Sports reported, "The president turned players' protests of systemic racism and police brutality during the national anthem into one of the core issues of his Twitter and media focus over the last several weeks, and Tuesday morning he continued that focus, while also appearing to target the league's tax status."

"Why is the NFL getting massive tax breaks while at the same time disrespecting our Anthem, Flag and Country? Change tax law!" the president tweeted.

While it's impossible to know exactly what he meant by "tax breaks," it should be noted that the NFL gave up its tax-exempt status in 2015, filing returns as a taxable entity for the first time in 73 years.

But PolitiFact also reports, "the bottom line is that the NFL continues to benefit from major tax breaks, especially in the construction of its stadiums."

White House Press Secretary Sarah Huckabee Sanders didn’t provide any details on the tax reform Trump was calling for in a press conference, but she did point to the stadium issue:

"While the NFL may have given up its tax-exempt status a few years ago, it's been well-documented that billions of taxpayer dollars continue to subsidize the construction and renovation of professional sports stadiums," Sanders said. "If this industry is going to use money from American taxpayers to build the very fields they play on, is it really too much to ask that they show respect for the American flag at the beginning of the game?"

So can Trump kill the stadium tax breaks? Reuters points out "Trump could propose tax reform legislation to remove the federal tax exemptions on debt financing for stadiums. However federal changes would not necessarily hinder any potential incentives offered by state and local authorities." In the same article, Reuters also noted. "Laws allowing teams to fund stadiums with tax-exempt bonds have cost the United States $3.7 billion in lost tax revenue from 2000 through 2014, according to a Brookings Institution paper released last year."

(CBS Sports contributed to this report.)