Candidates typically run for president either because they can win or because they want to draw attention to a given set of issues. Then there's Tom Steyer.

The liberal activist and megadonor announced his candidacy on Tuesday, and it isn't clear what he's hoping to accomplish as a candidate that he cannot already achieve as a billionaire.

In a field of two dozen candidates, Steyer's path to victory is limited. He may think that because President Trump won the presidency as a businessman without prior political experience, that he can, too. But Trump was a unique beast who had been a national celebrity, star of a hit TV show, and somebody who had decades of experience manipulating the mass media to promote himself.

In contrast, Steyer is unknown to most people outside of politics. The anti-corporate message in his announcement video is well represented within the current field of two dozen Democrats, and his delivery was flat. So, he's unlikely to actually have a chance at the nomination.

That brings us to the second reason people sometimes run for president, which is to draw attention to an issue or given set of issues. But as a billionaire, Steyer can do that now. Whenever he wants, he can rent time on television or use the internet to get out his message, as he has already done on impeachment and climate change. He could also contribute to Democratic House and Senate candidates in an effort to build a governing majority for his liberal ideas.

Instead, he's expected to spend at least $100 million of his own money on a presidential run. Incidentally, one of the qualifications for participation in the Democratic debates this month is to have at least 65,000 donors; and for September, to have 130,000 unique donors in at least 20 states. But a billionaire signaling out of the gate his intention to spend nine figures of his own money doesn't help efforts to convince small donors to support his campaign, thus it's far from certain he'll ever end up on the stage.

It seems that the biggest winners from this announcement are the RNC and Trump, who can now count on Steyer to waste a ton of money in a Democratic primary that otherwise could have been deployed against Republicans.