For Philip Morris dividend investors, the strength of the Marlboro brand is paramount. Photo: Nikita2706, via Wikimedia Commons. 

When it comes to investing, there are gray areas when it comes to morality.

Companies turn a profit in many different ways. For instance, Whole Foods (NASDAQ:WFM) does so by offering up food that's not only good for shoppers, but the earth as well. Philip Morris (NYSE:PM), on the other hand, does so by selling cigarettes, one of the most addictive, and harmful, products out there.

No debate over the morality of investing in cigarettes can be definitely solved. One thing, however, is definitive: Owning Philip Morris's stock has been very good for investors. Though the company has changed since spinning out Altria (NYSE:MO), Philip Morris was the single best performing stock in the S&P 500 since 1957.

That largely was the result of the company's outsized dividend. But how healthy is that dividend today, and will the stock continue to be a winner?

The most important metric for dividend investors
When it comes to a company's dividend, no metric is more important than free cash flow, or FCF. This is a measure of how much money a company puts in its pocket, minus any capital expenditures. Luckily for a company like Philip Morris -- which already has a robust network built out -- capital expenditures tend to be pretty low.

Here's what Philip Morris's dividend situation has looked like since 2009.

A few things stick out. First of all, for a long time, the company's dividend payout -- which now registers a whopping yield of 4.5% -- was very safe. Back in 2011, less than half of the company's FCF was being used to pay its dividend. Since then, however, trends have worked against the payout, and the dividend now accounts for 80% of free cash flows.

Because Philip Morris's capital expenditures are already low, that doesn't leave much wiggle room for future growth. If more money doesn't start coming in soon, Philip Morris is going to have a tough time raising its dividend.

The main thing to keep in mind here is the effect of currency exchange rates. Because Philip Morris International is focused solely abroad, those impacts mean more than they do for other countries. That, plus a 4% decline in sales in Asia -- which accounts for more than one-fourth of Philip Morris's sales -- has helped put the company in the situation its in today.

It's important to note that even if Philip Morris can't continue to raise its dividend, the company will still likely be able to maintain an outsized payout.

What does the future look like?
Knowing what we do about the company's dividend, it's also very Foolish to investigate what the future looks like for Philip Morris.

Originally, when it was spun out of Altria, many thought Philip Morris would be the cigarette growth story, with a focus on emerging markets. But while both revenue and earnings jumped nicely between 2009-2013, they've both retreated over the last 12 months.

Again, currency headwinds play a big role in this, and that needs to be taken into consideration. Without them, revenue and earnings would have continued growing at a nice pace.

But investors also can't ignore the larger trends working against the cigarette industry right now. While the decline of smoking in America has been well documented, trends are far more difficult to track abroad. The World Health Organization says that, "Only one in four countries, representing just over a third of the world's population, monitor tobacco use by repeating nationally representative youth and adult surveys at least once every five years."

That being said, the emergence of e-cigarettes, which are less harmful to both users and those around them, could be a slow deathblow for the entire global industry. It's going to take a long time before e-cigs begin to take significant market share away from traditional players, but it's a movement that long-term, buy-to-hold dividend investors need to be aware of nonetheless.

Currently, Philip Morris is trading at a fairly significant discount to its closest competitors, and the market at large. That being said, with sales somewhat stagnant and earnings plateauing, I'm not 100% convinced it's worth paying for a company trading at 16 times earnings.

In short, despite the outsized dividend, I think there might be better options out there for you.