The NFL, for its part, was not all that eager to continue the back-and-forth with Trump. "He's exercising his freedom to speak," league spokesman Joe Lockhart said on a conference call with reporters, "and I'm exercising my freedom not to react."
Asked about the possibility of the NFL punishing players or league employees for actions during the pregame anthems, Lockhart said: "I will leave the hypotheticals and the speculation to others. I'm not going to go down that road."
Trump brought up the topic for the fifth day in a row, dating to a speech to a crowd of supporters in Alabama on Friday night, when he referred to an NFL player making a gesture during "The Star-Spangled Banner" as a "son of a bitch."
In response, more than 200 players knelt or sat on a bench or took other actions during the anthems at games Sunday. On Monday night, Dallas Cowboys owner Jerry Jones — a staunch supporter of Trump — and his players knelt, arm-in-arm, before the anthem, then rose for the playing of the song ahead of the team's 28-17 victory at the Arizona Cardinals.
Some spectators at Arizona's stadium booed while the Cowboys knelt, which Trump tweeted was the "loudest I have ever heard." Among his other tweets Tuesday: "The NFL has all sorts of rules and regulations. The only way out for them is to set a rule that you can't kneel during our National Anthem!"
And this : "Ratings for NFL football are way down except before game starts, when people tune in to see whether or not our country will be disrespected!" The ratings for Monday's Cowboys-Cardinals game were up 63 percent from the equivalent game a year ago, which went up against a presidential debate between Trump and Hillary Clinton. The ratings for Week 3 of the NFL season were 3 percent higher than the same week last season.
But viewership for national telecasts of NFL games is down 11 percent this season compared with 2016 through three weeks, according to the Nielsen company. That figure does not include Monday's game. Still, five of the 10 shows with the largest prime-time viewership numbers last week were NFL-related telecasts.
At a White House news conference Tuesday, Trump was asked whether he's spent too much time thinking about the NFL instead of dealing with the crisis in hurricane-ravaged Puerto Rico. "Well, I wasn't preoccupied with the NFL. ... I don't think you can disrespect our country, our flag, our national anthem. To me, the NFL situation is a very important situation," Trump responded. "I've heard that before — about was I 'preoccupied.' Not at all. Not at all. I have plenty of time on my hands. All I do is work."
He went on to call kneeling during the anthem "disgraceful." Attorney General Jeff Sessions weighed in, too, condemning NFL players who exercised their freedom of expression by kneeling silently during the anthem.
"These players, with all the assets they have, can express their political views without in effect denigrating the symbols of our nation, a nation that has provided our freedom to speak," Sessions said during an appearance at Georgetown University's law school.
Tennessee Titans wide receiver Rishard Matthews, whose father is a retired Marine master sergeant and whose half-brother died in Afghanistan as a defense contractor, said Tuesday on ESPN's NFL Live that he will kneel until Trump apologizes.
"He was calling a lot of us, and I feel that he was calling myself, an S.O.B., and that's not OK and very disrespectful," Matthews said. "So I plan to kneel until the president apologizes." Former San Francisco 49ers quarterback Colin Kaepernick began kneeling during the anthem in the preseason a year ago to make a statement about social inequality and police treatment of blacks in the United States. Kaepernick currently does not have a job in the NFL; six players engaged in some form of protest during the anthem at games the week before Trump brought up the matter.
"Whatever you think about what has happened over the last four or five days, people are more aware of these issues than they were Friday at 9 o'clock," Lockhart said. "It's our job at every level of the league to make sure that we use this for good."
This story has been updated to include comments from Titans wide receiver Rishard Matthews that he plans to kneel until Trump apologizes for his comments.
Associated Press writer Sadie Gurman contributed to this report.
For more NFL coverage: http://www.pro32.ap.org and http://www.twitter.com/AP_NFL
Follow Howard Fendrich on Twitter at http://twitter.com/HowardFendrich