“So far, it’s all been 20,000-foot, feed red meat to the base … messaging. The Trump campaign has always made driving a narrative to the base a top priority,” Everhart said. “At the end of the day, you can’t build a house if you don’t have a solid foundation, and politically, the GOP base is that foundation for the president.”

Overall, Trump’s summer spending on national Fox News ads — more than 10 percent of the campaign’s total TV budget during that time, and more than the rest of its cable advertising combined — illustrated a strategy focused on the Trump base even as the campaign has talked about targeting swing-voting suburbanites, according to interviews with more than a half-dozen advertising experts and Republican strategists. It reflects Trump’s impulse to focus on friendly groups instead of those who may not have supported him in 2016. And the ad strategy raises additional doubts about whether the free-spending Trump campaign has made efficient use of the hundreds of millions of dollars it raised over the past four years.

Another Republican media strategist questioned the campaign’s approach. The person said Trump needs a bigger presence on entertainment channels in order to capture non-news-watching voters. “News channels are big in Washington, D.C., but are swing voters … watching news channels?” the strategist said. “To miss out on that audience is pretty large.”