Even in a political season marked by unprecedented levels of political spending, Sheldon Adelson stands alone.
In recent days, Mr. Adelson, a billionaire casino owner, and his wife, Dr. Miriam Adelson, gave $10 million to Restore Our Future, a “super PAC backing the Republican presidential candidate Mitt Romney, people with knowledge of the contribution said on Wednesday, leaving the Adelsons by far the most prolific campaign donors in the country.