More than 90 Honor Flight veterans visited the memorial, many of them from the Kansas City and Franklin County areas of Missouri.
As McCaskill shook hands and greeted the veterans, she said Tea Party Republicans were politicizing the event.
Referring by name to Rep. Michelle Bachmann, R-Minn., McCaskill apologized to the veterans from her district for all the fuss.
“Politics about veterans is bad manners," she said.
One veteran paused to shake McCaskill's hand.
"Really nice to finally meet you," he said. "Even though I'm a Republican. Don't worry, it won't rub off."
McCaskill was joined at the memorial by Missouri's other senator, Republican Roy Blunt.