Thomas Riley Marshall was vice-president under US President Woodrow Wilson from 1913-21. When Wilson suffered a mild stroke in September 1919, and a severe one in October that same year -- leaving him partially paralysed and incapacitated -- Marshall found himself close to the presidency. Crucially, however, Wilson's adviser and his wife, Edith Wilson, disliked him.
The first lady opposed the vice-president assuming the presidency, and made sure there was no official communication between Wilson's staff and Marshall about the president's health. The secretary of state, Robert Lansing, introduced a proposal that would require Marshall to assume leadership, but Marshall said the only conditions under which he would take over were if Congress called on him to do so, or if official communication conveyed Wilson's inability to perform his duties.
Wilson's wife continued to keep her husband secluded and refused to disclose any details of his condition. Marshall received few updates and was unable to learn more.
He attended some ceremonies on the president's behalf, but Edith Wilson performed most of the executive duties. She is sometimes referred to as the first female president of the United States. Marshall did not see Woodrow Wilson, or get any real sense of his state of health, until his last day of office.
In 1920, Marshall sought the Democratic presidential nomination but lost support for his bid. When the Republicans Warren G Harding and Calvin Coolidge took over the White House, Marshall is said to have sent Coolidge a note offering his condolences on the misfortune of being elected vice-president.