Let's Play Ball

In 1916, during WWI, President Woodrow Wilson ordered that the Star-Spangled Banner be played at military events, and two years later, it was played during the 7th Inning Stretch at the 1918 World Series.
Thus began a wartime tradition. 

During the Second World War, the National Anthem began to be performed before every game.  It has been asserted that this was not solely due to patriotic zeal but also to make sure the fans didn't question the patriotism of the players who weren't fighting in the war.

Peace came but the anthem played on.  During the Vietnam War, at the 1968 World Series in Detroit, Jose Feliciano sparked enormous controversy by performing a soulful rendition that was deemed disrespectful.  This eventually paved the way for countless non-traditional versions which could be poorly rendered as long as they were considered respectful. Rosanne Barr's attempt at a comedic version at a 1990 Padres games was widely trashed, with then-President Bush calling it "disgusting." And Michael Bolton was lambasted after his 2003 American League playoff game performance when he forgot the words midway through and had to rely on a cheat sheet.

After 9/11, one song did not seem sufficient for players and fans to express their love of the United States, and Irving Berlin's God Bless America began to be sung during the 7th Inning Stretch, either instead of or in addition to Take Me Out To The Ballgame.  It is played during every game at some ballparks, like Yankee Stadium, as well as at All Star Games and the playoffs and World Series.

Those who believe that this nationalist fervor is misplaced are shouted down.  When Toronto Blue Jays slugger Carlos Delgado refused to stand with his teammates during God Bless America in protest of the war in Iraq he was booed and roundly criticized.  In 2008, during a Yankee game, a fan who tried go to the bathroom while the song was playing was restrained and ejected.  Anyone who doesn't stand and remove their hat during either song will likely find a beer poured over their head.  Baseball remains America's Pastime. 

However, it has never been clear to me why we must reaffirm our love of this country -- including the 28% of  Major League Baseball players who are foreign born -- not once, but twice during a baseball game.  It seems to me that we show our faith in what is great about the United States by enjoying the great American game itself, and I truly believe there are few things more patriotic than standing up during the 7th Inning Stretch and singing about "peanuts and crackerjacks" at the old ballgame.