A key component is missing from the current controversial discussion surrounding football players and the national anthem. In the recent days of argument over whether NFL players have the right to protest racial inequality and systemic injustice in the United States, few have brought up the fact that less than a decade ago, professional football players didn’t even appear on the field during the national anthem.

That changed in 2009, as the Department of Defense poured millions of dollars into the NFL in exchange for displays of patriotism during games. “Until 2009, no NFL player stood for the national anthem because players actually stayed in the locker room as the anthem played,” ESPN’s Stephen A. Smith explained in 2016. “The players were moved to the field during the national anthem because it was seen as a marketing strategy to make the athletes look more patriotic. The United States Department of Defense paid the National Football League $5.4 million between 2011 and 2014, and the National Guard $6.7 million between 2013 and 2015 to stage onfield patriotic ceremonies as part of military-recruitment budget line items.”

NFL spokesman Brian McCarthy later confirmed that players did not appear on field for the anthem until 2009, and Vice notes that Smith’s claim was checked by an ESPN researcher.

Urging players to appear onfield during the national anthem is just one example of “paid patriotism,” a practice tackled by Sen. John McCain and Sen. Jeff Flake in 2015. A joint report issued by the senators goes into even further detail about how the DOD financed displays of patriotism with taxpayer dollars:

For the past several months, we have continued to work with DOD to fully understand the nature and extent of these contracts. In all, the military services reported $53 million in spending on marketing and advertising contracts with sports teams between 2012 and 2015. More than $10 million of that total was paid to teams in the National Football League (NFL), Major League Baseball (MLB), National Basketball Association (NBA), National Hockey League (NHL), and Major League Soccer (MLS). … While we fully support the intent of the coaches and players programs and understand the need to cultivate long-term relationships with individuals who can influence the decisions of prospective recruits, we find the tactics used by the military services questionable and the benefit to taxpayers undefined. If the most compelling message about military service we can deliver to prospective recruits and influencers is the promise of game tickets, gifts, and player appearances, we need to rethink our approach to how we are inspiring qualified men and women to military service. Unfortunately, contrary to the public statements made by DOD and the NFL, the majority of the contracts—72 of the 122 contracts we analyzed—clearly show that DOD paid for patriotic tributes at professional football, baseball, basketball, hockey, and soccer games. These paid tributes included on-field color guard, enlistment and reenlistment ceremonies, performances of the national anthem, full-field flag details, ceremonial first pitches and puck drops. The National Guard paid teams for the “opportunity” to sponsor military appreciation nights and to recognize its birthday. It paid the Buffalo Bills to sponsor its Salute to the Service game. DOD even paid teams for the “opportunity” to perform surprise welcome home promotions for troops returning from deployments and to recognize wounded warriors. … The DOD’s complete lack of internal controls for awarding, managing, and overseeing these contracts puts them at an excessive risk for waste, fraud, and abuse. Beyond being a question of if this contracting activity reflects appropriate judgement or fiscal stewardship of taxpayer funds, the fundamental question at hand is if this spending reflects appropriate national security priorities. In 2014, while the National Guard was spending millions on professional sports advertising, it was simultaneously requesting additional funds from Congress to cover a more than $100 million shortfall to pay its troops and conduct critical training.

The report found that “[s]eventy-two of the 122 (59 percent) major league contracts analyzed contained items deemed ‘paid patriotism’ — on-field color guard, enlistment and re-enlistment ceremonies, performances of the national anthem, full-field flag details, ceremonial first pitches and puck drops, and hometown hero and wounded warrior tributes.”

According to McCain, the Pentagon spent $6.8 million over the course of several years for such patriotic displays.

Now, in the wake of President Trump’s attack on players who kneel during the anthem, the origins of the practice matter more than ever.

The topic was briefly discussed on MSNBC this week, when NFL player Marvin Washington brought up the financial relationship between the DOD and the NFL. Civil rights activist Jesse Williams also brought up paid patriotism in an MSNBC interview this week, calling the anthem a “scam.”

“This is not actually part of football. This was invented in 2009 from the government paying the NFL to market military recruitment to get more people to go off and fight wars to die,” he said. “This has nothing to do with [the] NFL, or American pastime, or tradition. … This is to get boys and girls to go fly overseas and go kill people. They’re marketing. They’re pumping millions and millions of dollars into the NFL to get us to put on a pageant in front of the NFL football games to get you to go off and fight.”

However, the original opponents of paid patriotism, Sens. McCain and Flake, in the past week haven’t once publicly mentioned the Pentagon’s financial influence. Notably, McCain stated this week he supports players’ rights to protest, but neither he nor Flake has brought up the troubling findings of their 2015 report.