The National Portrait Gallery changed a caption that accompanied a portrait of President Bush after Sen. Bernie SandersBernie SandersTim Ryan says he's 'looking seriously' at running for Portman's Senate seat Bernie Sanders has been most-followed member of Congress on social media for six years This week: Senate stuck in limbo MORE (I-Vt.) complained about it, reports CNSNews.

Sanders said that the caption in wrongly linked the 9/11 attacks to the U.S.-led invasion of Iraq.

The caption initially read as follows:

"Expecting that the success of his presidency would hinge, as it had when he was governor, on his negotiating skills and ability to solve problems, Bush found his two terms in office were instead marked by a series of catastrophic events: the attacks on September 11, 2001, that led to wars in Afghanistan and Iraq; the devastation wrought by Hurricane Katrina; and a financial crisis during his last months in office."

Sanders, an opponent of the Iraq war from the start, took issue with the notion that the terror attacks "led to" the Iraq war. He wrote a letter to the National Portrait Gallery's director about the caption last week, and the gallery then removed the words "led to."

"Our label was not intended to imply that there was a causal connection between the attacks that occurred on 9/11 and the subsequent U.S. invasion of Iraq," wrote gallery director Martin Sullivan in a letter to Sanders. "Our intention was to remind viewers of the portrait that the listed events were defining episodes in the Bush presidency, within the limited space of an object label."

Sullivan added that he would call Sanders's office to try to arrange a personal tour of the gallery.