Clark served as president of both Montana state constitutional conventions in 1884 and 1889.

Clark yearned to be a statesman and used his newspaper, the Butte Miner, to push his political ambitions.
At this time, Butte was one of the largest cities in the West.
He became a hero in Helena, Montana, by campaigning for its selection as the state capital instead of Anaconda.
This battle for the placement of the capital had subtle Irish vs. English, Catholic vs. Protestant, and non-Masonic vs. Masonic elements.
Clark's long-standing dream of becoming a United States Senator resulted in scandal in 1899 when it was revealed that he bribed members of the Montana State Legislature in return for their votes.
At the time, U.S. Senators were chosen by their respective state legislatures.
The corruption of his election contributed to the passage of the 17th Amendment.
The U.S. Senate refused to seat Clark because of the 1899 bribery scheme, but a later senate campaign was successful, and he served a single term from 1901 until 1907.
In responding to criticism of his bribery of the Montana legislature, Clark is reported to have said, "I never bought a man who wasn't for sale."

Clark died at the age of 86 in his New York City mansion.
His estate at his death was estimated to be worth $300 million, (equivalent to $4,373,624,000 in today's dollars), making him one of the wealthiest Americans ever.

In a 1907 essay, Mark Twain, who was a close friend of Clark's rival Henry H. Rogers, an organizer of the Amalgamated Copper Mining Company, portrayed Clark as the very embodiment of Gilded Age excess and corruption:
He is as rotten a human being as can be found anywhere under the flag; he is a shame to the American nation, and no one has helped to send him to the Senate who did not know that his proper place was the penitentiary, with a ball and chain on his legs.
To my mind he is the most disgusting creature that the republic has produced since Tweed's time.
Clark served as president of both Montana state constitutional conventions in 1884 and 1889.
Clark yearned to be a statesman and used his newspaper, the Butte Miner, to push his political ambitions. At this time, Butte was one of the largest cities in the West. He became a hero in Helena, Montana, by campaigning for its selection as the state capital instead of Anaconda. This battle for the placement of the capital had subtle Irish vs. English, Catholic vs. Protestant, and non-Masonic vs. Masonic elements. Clark's long-standing dream of becoming a United States Senator resulted in scandal in 1899 when it was revealed that he bribed members of the Montana State Legislature in return for their votes. At the time, U.S. Senators were chosen by their respective state legislatures. The corruption of his election contributed to the passage of the 17th Amendment. The U.S. Senate refused to seat Clark because of the 1899 bribery scheme, but a later senate campaign was successful, and he served a single term from 1901 until 1907. In responding to criticism of his bribery of the Montana legislature, Clark is reported to have said, "I never bought a man who wasn't for sale."
Clark died at the age of 86 in his New York City mansion. His estate at his death was estimated to be worth $300 million, (equivalent to $4,373,624,000 in today's dollars), making him one of the wealthiest Americans ever.
In a 1907 essay, Mark Twain, who was a close friend of Clark's rival Henry H. Rogers, an organizer of the Amalgamated Copper Mining Company, portrayed Clark as the very embodiment of Gilded Age excess and corruption:
He is as rotten a human being as can be found anywhere under the flag; he is a shame to the American nation, and no one has helped to send him to the Senate who did not know that his proper place was the penitentiary, with a ball and chain on his legs. To my mind he is the most disgusting creature that the republic has produced since Tweed's time.
William A. Clark