It’s a truism in politics that everyone running for any office, even one as down ballot as dogcatcher, has presidential aspirations.

So it should come as no surprise that according to a Beltway insider working on the proposed merger of Sinclair Broadcast Group and Tribune Media Co., one reason that some Hill Republicans, as well as Democrats, are beginning to review the deal skeptically comes down to “someday, I want to be President.”

Here’s why.

As it stands, unless divestment occurs and if the merger goes through, the bigger, post-deal Sinclair will own both the Fox and NBC affiliates in the Des Moines media market.

That matters because presidential nominating contests, of course, kick off in Iowa. And Des Moines is not only the major urban center of the state. Its market also covers Ames, the home of the Iowa straw poll. That poll was killed in advance of the 2016 nominating process, but theoretically, it could be brought back to life.

And it turns out that a lot of would-be presidential contenders are worried about the prospect of a network that could view their future candidacies more or less favorably, depending on the editorial line taken by Sinclair headquarters, having such a massive role in potentially influencing the outcome of the Iowa caucuses.

This is a particular concern with regard to Sinclair, as opposed to other broadcasters, because so much of its content is dictated by its national headquarters, which mandates “must-run” segments that its local affiliates have to fit into their coverage.

Because Sinclair is seen as being explicitly pro-Trump, with its segments featuring former Trump staffer Boris Epshteyn often being mocked as the equivalent of North Korean news broadcasts, Sinclair’s potential future control of two major stations in Des Moines is a big concern for would-be Trump primary challengers.

But Sinclair’s likely dominance of the Des Moines media market, in the absence of divestitures, is also concerning future presidential prospects who like Trump or have been Trump-neutral, but who doubt whether he could run again.

Reportedly, senators ranging from Tom Cotton (R-Arkansas) to Marco Rubio (R-Florida) to Ted Cruz (R-Texas) have nominally toyed with the idea of running again in 2020, depending on how the rest of Trump’s term pans out.

In addition, a number of current and former Republican governors are said to be keeping an eye on Trump’s political fortunes, as it is possible he will not run in 2020, and depending on certain key events, Vice President Mike Pence could potentially be politically tarnished enough to either not run for President in 2020, or lose a nominating contest. Notably, in 1988, Vice President George H. W. Bush came third in Iowa’s caucuses– an indicator that some advisers to would-be presidential candidates see as an indicator that a Pence run need not necessarily be a lay-up.

Currently, the merger “shot clock” has been paused, though it is expected to begin ticking again soon. It is unclear what, if any, divestitures Sinclair is willing to make in order to diminish concerns about excessive media ownership in given markets, including Des Moines.

So, for as long as that remains the case, expect this merger to be more controversial than experts expect.