It's difficult to remember who Tom Steyer is.

The answer, if your memory needs a jog as much as mine, is a billionaire finance guy who numbers among the infinity Democratic candidates hoping to challenge President Trump in 2020. Since announcing his campaign in early July, Steyer has steadily outspent the rest of the Democratic primary field on television ad buys. In fact, until mid-November, he consistently spent more than all the other candidates combined. To date, FiveThirtyEight estimates Steyer has dropped around $46 million on TV ads. And yet, per the RealClearPolitics average, he is polling at all of 1.7 percent.

With numbers like that, does campaign cash matter anymore?

Conventional wisdom, especially in the post-Citizens United era, holds that access such a massive war chest is access to victory — that money is a corrupting force in politics which allows corporations and rich individuals to buy power in a way the poor and middle class struggle to replicate, even with collective action. In her final general election debate with then-candidate Donald Trump in 2016, Hillary Clinton argued for the need to fashion "a Supreme Court ... that will stand up to Citizens United, a decision that has undermined the election system in our country because of the way it permits dark, unaccountable money to come into our electoral system." (Naturally, she has since proceeded to avail herself of exactly that sort of money.)

This conventional wisdom isn't entirely wrong. It would require a bizarre and willful naivete to pretend money has no effect in politics, that Americans are universally diligent voters who make sure they give each candidate an equally fair shake. If you're running a remotely viable, national campaign for president, you do need millions of dollars. Note that in all of the last 10 presidential elections, the candidate who spent more in the general won — except, that is, for President Trump, who was substantially outspent by Clinton in 2016 and also received less support from single-candidate super PACs.

Trump was likewise outspent by all his 2016 primary opponents but former Ohio Gov. John Kasich (R) if you look at his to-date spending at the time of their withdrawal from the race. His last competitive challenger, Sen. Ted Cruz (R-Texas), spent more overall, $85 million to Trump's $63 million in the primary season. Yet more money did not mean more votes for Cruz, nor for former Florida Gov. Jeb Bush (R), Ben Carson, or Sen. Marco Rubio (R-Fla.).

In this cycle's Democratic primary, Steyer isn't the only one for whom dumping big bucks on TV ad buys isn't working. His fellow billionaire and former New York City Mayor Michael Bloomberg got into the race in late November and seems to be using a backhoe to deliver dollars to TV networks ever since. In less than three weeks, FiveThirtyEight calculates Bloomberg has spent as much on TV ads as Steyer paid since July — $46 million. His polling average is a more impressive 5.5 percent, but it doesn't look so hot next to the far stronger support frontrunners have netted with far less ad spending.

Of course, TV ads aren't the only financial measure of a presidential campaign. If you look at the bigger picture of money in and out of 2020 Democrats' campaigns (Bloomberg isn't on the list yet because of the recency of his official candidacy), more popular contenders do have more money. But the correlation is far from perfect: Sen. Bernie Sanders (I-Vt.) has taken in nearly double former Vice President Joe Biden's fundraising this quarter, for example, but averaged just over half his support. And there's Steyer with his extravagantly self-funded campaign — and margin-of-error voter enthusiasm — right at the top of the list.

There are a couple takeaways here, I think. One is that previously ignored and comparatively small expenditures may become indirectly important. I'm thinking here of recent reports on campaign staff salaries and union organizing. For Democrats, cooperating with a union and paying workers a good wage will earn organic positive attention an ad can't replicate. For the GOP, differing political priorities mean a comparable move might be something like only selling U.S.-produced campaign gear. The Trump campaign touts this very thing (though another official Trump store mostly sells foreign-made merch).

Another, bigger lesson is that money doesn't function in presidential politics (smaller races can work very differently) as it did in the past. (It will be interesting to see the dynamics here in the next true GOP primary: Republican voters tend to skew older and so may be a better audience for traditional campaign expenditures like TV ads — but again, Trump didn't win the 2016 primary or general election by outspending his competition.) You cannot buy your way to the top five in a crowded primary field. Even name recognition and basic biographical awareness is increasingly difficult to purchase if voters simply are not interested in you and your message, while candidates who generate legitimate grassroots enthusiasm can attract a large following on a relatively small budget.

Money in politics absolutely still matters, but its effects are increasingly uncertain. That Democrats aren't looking at a Steyer-Bloomberg race makes that inescapably clear.