The 2020 presidential election will be the most expensive election ever, and most of the money will be used on political advertising. Industry experts predicted in September that $10 billion would be spent, a 60 percent increase in ad spending from 2016 — and that was before Michael Bloomberg’s entry into the Democratic primary and the record-breaking $57 million he spent in just his first week as a candidate.

Will all that ad spending matter? Yes and no: These advertisements will have effects, but not on voters. The majority of evidence in political science finds that political ads have limited effects that are short-lived. Individual ads may persuade temporarily by informing voters or triggering an emotional response, but the effects are small in the real world and cancel each other out when ads are aired in equal volume.

This massive infusion of political cash into the media will benefit tech companies and cable news networks more than in previous cycles — reinforcing trends in the media industry that are hurting politics in America today and causing more damage than any negative ad.

The major tech companies are receiving more and more campaign cash. For example, including search ads (and despite their “new rules”), Bloomberg bought $4.6 million in advertising from Google in his first week — more than the entire Democratic field combined had to that point.

Federal regulations disadvantage local news stations in today’s environment. The FCC regulates rates of television ads and demands that stations disclose those rates, but no such regulations exist for online advertising. Traditionally, campaigns have focused their limited resources on ads on local broadcast channels in targeted markets in swing states, but local television ownership is consolidating and these ads will benefit ownership groups as well as individual stations. Local newspapers also receive none of this money for print ads (though there is quite a bit of digital advertising on local newspaper websites, at much lower rates).

The shifting of spending to national cable and online platforms will hasten current trends in the media environment, such as the nationalization of political decision-making. Politics, and political news, are gradually becoming a referendum on the president and what’s going on in Washington, as local news struggles to adapt to the changing economics of news and preferences of consumers.

The unbelievable spending we’re already witnessing will make cable news, tech companies, and owners of television stations richer, while benefiting local news less than ever.