When Democrats and Republicans take to the field at RFK Stadium tonight for the 46th Annual Roll Call Congressional Baseball Game, they’ll do more than just compete for the coveted Roll Call trophy and their partisan honor. They’ll also be contributing to posterity.

That’s because since its formation five years ago, the House Office of History and Preservation has made a point of collecting items related to this summertime ritual.

“We aim to in some ways put a human face on the House … and this is one of the longest traditions,” said Farar Elliott, the office’s curator and chief. “We go to the games, and we do go around to Members’ offices and ask them for their [game] baseball cards.”

So far, the House has acquired about 50 pieces related to the game and its key players, Elliott said, some of which are highlighted in an exhibit on the House Clerk’s Web site. Among the contemporary memorabilia the office seeks out are tickets, programs and Members’ baseball cards.

The earliest item in the House’s baseball collection is a tiny, dime-sized pin from the 1910 gubernatorial campaign of then-Rep. John Tener (R-Pa.), a former pitcher for the Chicago White Stockings who organized the first Congressional Baseball Game in 1909. (The game was played sporadically from then until 1946, when the now-defunct Washington Evening Star signed on as sponsor. It was halted briefly in the late 1950s and early 1960s, before Roll Call brought the tradition back in 1962.)

The House also holds the Major League Baseball cards of former stars of the diamond who would go on to serve in Congress and make their mark in its game. Among the collection is Baseball Hall of Famer Sen. Jim Bunning’s (R-Ky.) 1958 Detroit Tigers card and the late Rep. Wilmer David “Vinegar Bend” Mizell’s (R-N.C.) 1953 card from his days as a left-handed pitcher with the St. Louis Cardinals.

Mizell “was a ringer for the Republicans,” said Erin Hromada, a historian in the History and Preservation Office who has researched the game. She added that “whichever team had a better pitcher is generally the team that won.”

Elliott, who said her office is always on the lookout for items from games past, admits to scouring Washington, D.C., flea markets, baseball card swaps, political memorabilia sales and even eBay in search of artifacts related to this annual showdown.

Sometimes items serendipitously make their way into the collection.

Two years ago, the office conducted an oral history interview with Glenn Rupp, a 1930s-era Congressional page who later donated his 1932 game program to the House’s collection.

“He was very excited that the box score for the 1932 Congressional Baseball Game would at long last have a place in the pantheon of sports that it ought to,” Elliott quipped. The back of the program includes a rather humorous ad for a printing company, which declares: “We print for both Democrats and Republicans (also Insurgents).”

That year, in the midst of the Depression, the game’s proceeds were donated “to the benefit of the D.C. unemployed,” according to the program. (With the exception of 1909, all known games have been played for charity. Hromada conceded there are a few periods for which no information is available, such as 1920-1925 and 1933-1944.)

The items also help illustrate how the game has both changed and remained the same over the years.

In 1926, Hromada noted, pointing to a black-and-white photo, the game’s fanfare included “Republicans parading in on an elephant,” the presence of a live donkey to represent the Democrats, Navy band performances and an appearance by President Herbert Hoover. (There is no record of presidents attending the game since Dwight Eisenhower did so in 1953, said Hromada.)

Then there are the uniforms.

“In the beginning they wore no-name uniforms and put a sash on it” denoting whether they were a member of the Republican or Democratic teams,” said Hromada. Today, Members often wear jerseys from teams in their home state.

Of course, some things haven’t changed — for instance, trophies are still awarded, though a photo accompanying a 1927 New York Times article is the only proof of their early existence, said Hromada. “We’d love to get our hands on them,” she added.

And despite evidence to the contrary, the notion that the game’s outcome has greater implications for the ballot box continues to resonate with partisan fans.

The 1932 program bears the motto: “As the game goes, so goes the election.”

It was a prediction that couldn’t have been more wrong that year.

The Republicans may have won that contest, but any joy would be short-lived. That November, Democrats would get their revenge at the voting booth. And GOPers saw their Congressional majority upended with more than 100 seats lost.