This article is part of our Rising Star Portfolio series.

I recently highlighted five stocks I believe are particularly safe investments from the Rising Star portfolio I'm managing for Now, I've decided to try another exercise: which stock am I most likely to sell? First Solar's (Nasdaq: FSLR) really been trying my patience recently.

When good only goes so far
Granted, there are a few weak silver linings surrounding First Solar's clouds, even as the stock has dropped about 65% since my September purchase. For example, although the solar industry overall is beset with challenges, First Solar has clout as an industry leader. The stock looks cheap, too; it trades at just eight times forward earnings, and has a PEG ratio of just 0.35.

First Solar has also garnered some impressive deals. For example, it sold its Topaz solar farm to MidAmerican Energy, a unit of Berkshire Hathaway (NYSE: BRK-B), adding the missing component of sun power to MidAmerican's existing portfolio of traditional power plants and wind farms.

Granted, deals like this one back up the theory that solar power is increasingly ready for prime time -- and more likely to find private-sector support, although tax incentives are also arguably generating more private-sector interest in solar power these days.

Just as dirty as Big Oil?
On the other hand, troubling issues have cast shadows over my original enthusiasm for First Solar shares.

In October, First Solar ditched then-CEO Rob Gillette with little disclosure as to exactly why, although there's good reason to have looked askance at his tenure. In his first 15 months on the job, he raked in more than $30 million in compensation as the stock dropped 60%, and he may be eligible for $8.9 million in severance.

For some added perspective, Gillette's compensation was 19% higher than that of Chevron's (NYSE: CVX) chief executive officer at that time, while Chevron share price had increased by 54%.

Frankly, I've become worried about how First Solar's board devises executive compensation. Gillette even received a $5 million signing bonus to convince him to come aboard from his previous post at Honeywell.

Since then, under founder and interim CEO Mike Ahearn, First Solar has let loose a stream of challenging news. It's reorganizing (and letting go 100 workers) as it switches focus from small rooftop solar installations to mammoth solar farms.

Bloomberg recently reported that First Solar has somehow managed to outspend BP (NYSE: BP) in lobbying politicians for aid. Since 2007, the company has spent $2.2 million on Washington lobbying, and it gave $150,000 to California political campaigns last year, far more than BP's North American unit shelled out in that state ($38,750).

In other words, some companies formulating alternatives to Big Oil may be actually following in its crude footsteps. According to the Center for Responsive Politics, the oil and gas industry ranked third in lobbying expenditures in 2011, shelling out about $110.7 million.

First Solar's lobbying and campaign contribution expenditures are a drop in the proverbial bucket compared to the oil and gas set, which includes behemoths like ExxonMobil (NYSE: XOM), Chevron, and Occidental Petroleum (NYSE: OXY). You can check out a breakdown of such gigantic oil and gas companies' campaign contributions in 2011, as well as their massive lobbying expenditures. First Solar may be learning fast about spending money to gain political favor, though; the Center for Responsive Politics reports that its total lobbying expenditures in 2011 added up to $480,000 -- incidentally, nearly as much as failed solar outfit Solyndra.

Solar power is a clean, green, renewable energy source, but that doesn't mean the industry couldn't get dirty in other ways. One of the themes of 2011 has been the need to separate money and politics, and right now, it doesn't look like First Solar's showing a socially responsible or passionate path to profits. Instead, it simply sounds like it's got a case of Big Oil envy.

Save it or sell it?
On a strictly financial level, First Solar recently slashed its 2012 guidance; it now expects earnings of $5.75-$6.00 per share compared to the previous estimate of $6.50-$7.50 per-share profit. The company has lowered its sales guidance to $2.8 billion-$2.9 billion from October's expectations of $3 billion-$3.3 billion.

I can take lowered guidance in stride, as the fact that Chinese competition is making times tough for the U.S. solar industry is pretty common knowledge.

However, I can't take the other damning evidence lightly. Pared-down financial expectations seem more insulting when you realize money has been thrown around in ways shareholders shouldn't applaud, like huge signing bonuses, pay for failure, and political purposes. Nobody can blame China for that.

Since the Rising Stars project's inception, I've vowed to set up a long-term portfolio, so selling a stock after only a few months doesn't come naturally to me. I'm also aware of the pitfalls of selling when investors feel most negative about a company's future. Buying high and selling low stinks.

However, given recent events, I am beginning to wonder if First Solar's story is fundamentally changing. My Foolish colleague Travis Hoium recently outlined several ways to save this solar stock. At some point, though, it might be time to admit to a mistake and head for stocks with sunnier prognoses and far fewer unattractive attributes. I wanted to design this portfolio as one to feel good about, after all.

Do you think I should sell, hold, or buy more? Add your thoughts about First Solar in the comments below, or add First Solar to your Watchlist to track the ongoing developments.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.