A shibboleth of the enemies of direct democracy for choosing the president is this:

If every vote mattered equally no candidates would care about the votes in less dense or rural states.

On its face this claim seems self-contradicting. If every vote counted equally, then obviously every candidate would try to get every vote everywhere. The question would not be whether they wanted every vote, but rather how would they go after the votes in less dense areas. 

We already know the answer by looking at how major brands and retailers reach every possible customer. 

First, retailers invest in national branding. Currently in the general election presidential candidates spend almost nothing advertising on national television shows. If every vote mattered equally this would change. You’d see the president advertising on the Super Bowl, or for that matter, stalking the sidelines for “product placement.”

Second, in major urban areas the cost of reaching customers through broadcast or cable channels is much higher than in less dense areas. Therefore campaigns would proportionally spend less on television spots in dense areas, and much more on television in less dense areas. If you own a television station in the Dakotas, you should want the national popular vote to pick the president. Similarly there’d be political advertising on local radio in rural areas, whereas today there is none from the presidential candidates.

Third, the rise of social advertising is inexorable, because social advertisers can pick the target audience with more precision than can one-to-many advertising. Especially in dense areas, social would be preferred over old school techniques. But because distance is irrelevant for social advertising, the big social firms would be a platform for reaching every voter everywhere.  

Fourth, just as Wal-Mart ignores no one, so candidates would ignore no region in their search for votes. Very likely, in right-leaning states the effort to get out the vote for the Republican nominee would go up, because the Republicans currently gain nothing by seeking higher turn-out in the more rural states where they are the preferred party.

 Fifth, there is some evidence already that confirms these hypotheses. This is from the estimable web site Nationalpopularvote.com:

The fact that serious candidates solicit every voter that matters was also demonstrated in 2008 by Nebraska’s 2nd congressional district (the Omaha area). Even though each congressional district in the country contains only 1/4% of the country’s population, the Obama campaign operated three separate campaign offices staffed by 16 people there. … Mitt Romney opened a campaign office in Omaha in July 2012 in order to compete in Nebraska’s 2nd district and … the Obama campaign was also active in the Omaha area.

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In many cases, small states offer presidential candidates the attraction of considerably lower per-impression media costs …