In 1918 Henry Ford ran for the United States Senate as a Democrat, narrowly losing to Republican candidate Truman Newberry. Newberry won with 50.19% of the vote, while Ford had 48.47%. Shortly after the election Newberry was tried under the Federal Corrupt Practices Act for election irregularities. Although his conviction was overturned by the United States Supreme Court in Newberry vs. United States and a Senate investigation found him entitled to his seat, Newberry resigned in 1922. The Republicans only controlled the Senate by a single vote after the 1918 elections. If Henry Ford had won his race he would have tied the chamber and given control to the Democrats (with the Vice President casting the tie-breaking vote). In addition to Henry Ford's narrow loss in Michigan, the Democrats also narrowly lost Senate races in New Hampshire and Colorado. If Henry Ford had become a senator what kind of impact might there have been on the League of Nations and other legislative matters? Might Ford have gone on to have a greater career in politics?
Ford Motor Company would likely be even more successful if Henry Ford had to step away from the company for a few years. He was very resistant to change and thought the Model T was the most simple, rugged, and affordable vehicle possible. General Motors and other companies started acquiring market share among people who wanted something else from their vehicles. It took tremendous effort by Edsel Ford (who took official control in 1919, although with Henry still having a powerful influence) and company advisors plus a decline in Model T sales before the Model A entered production 1927. By that point the Model T had been in production for 18 years as Ford's first and only model.
He was a very popular person at the time, so he could run for President if he wanted. If he becomes a Senator he might not purchase the Dearborn Independent which published infamous anti-Semetic articles.
He did suffer a series of strokes in the late 1930s wich had him increasingly debilitated, and his mental ability was fading, so i think he would not be a good person to be president during World War II.