George McGovern has been admitted to a hospice, with his family reporting that the former Senator and Democratic presidential candidate is "no longer responsive."
McGovern was admitted to a hospice center in Sioux Falls, South Dakota this week, and his close family is said to have joined him at his bedside, according to Reuters.
The 90 year old is remembered for competing, and ultimately losing, to Richard Nixon in the 1972 presidential election.
His family has released a statement on Wednesday explaining that he had been admitted to a hospice "with a combination of medical conditions, due to age, that have worsened over recent months."
McGovern served in the United States Senate for South Dakota from 1963 to 1981.
He made a failed bid to unseat Nixon in 1972 on a platform opposing the war in Vietnam.
In a speech on the Senate floor in September 1963, McGovern became the first member to challenge the increasing United States military involvement in Vietnam. McGovern said: "The current dilemma in Vietnam is a clear demonstration of the limitations of military power ... [Current U.S. involvement] is a policy of moral debacle and political defeat ... The trap we have fallen into there will haunt us in every corner of this revolutionary world if we do not properly appraise its lessons."