It's been a bad week for Royal Bank of Scotland (NYSE:RBS) shareholders. First, the company has come under increased scrutiny for potential LIBOR rigging. According to recent reports, the company may face criminal charges, as well as fines from both U.S. and U.K. regulators. On top of that, a recent Reuters' report highlighted the foot-dragging that RBS has taken to in its attempt to sell of hundreds of its branches. But even these setbacks haven't put the bank off of its recent winning streak. The stock is up 26% over the past year, and 7% in 2013. If the recent madness hasn't put a dent in this bank's value, why wouldn't long-term investors consider it?

Citizen's Bank of Scotland
Since 1727, RBS has been printing currency. Now, it's one of only three banks that prints notes in Scotland . It seems fitting that those notes should be used by the government that guarantees their value to buy the bank when it falls apart. In 2008, RBS fell apart under the careless eyes of Fred Goodwin, and a majority stake was taken by the government in an attempt to save the bank from itself . The government now owns about 65% of the outstanding ordinary shares, but that total is bumped up to 82% of the RBS group if the government's B shares are included. So the U.K. is understandably upset about fines and bonuses, which do nothing to help its investment.

The alleged LIBOR rigging looks very much like the rigging that Barclays (NYSE:BCS) and UBS (NYSE:UBS) recently paid fines for. RBS employees are accused of submitting false rates in an attempt to either make money on positions the bank held that hinged on the LIBOR, or in an attempt to make the bank look more stable than it actually was. The recent news indicates RBS may also be handed a criminal charge.

UBS was in a similar position last year, and along with its $1.5 billion fine, it was forced to plead guilty to wire fraud . While there's a distinction to be made in the charges, they simply resulted in a slightly bigger overall fine for UBS . No one has gone to jail, but there are two outstanding felony charges against an English and a Swiss banker who worked at UBS at the time .

The long game
For investors, the whole LIBOR mess has been something of a blessing and a curse. On one hand, share prices haven't been overly damaged by the rulings -- Barclays is up 42% over the last year, while UBS a mere 27%. RBS investors probably don't have anything to worry about. On that other hand, share prices haven't been overly damaged by the rulings. It's all well and good for investors not to want to get hurt, but that they've been rewarded seems to mock the idea that there's any justice at all in the market.

Right now, there seems to be no financial reason not to invest in RBS. Even though the company is going to pay out $650 million and may face criminal charges, it's also backed by the U.K. government. It's not going to go to zero. In fact, the shares will likely jump once it can figure out how to ditch the 316 branches it's been trying to sell for years now. Last year, Santander was all lined up to purchase the lot, but it backed out in October after the process proved too difficult . Now RBS is sitting on bids it received in December of last year. I imagine an announcement will come shortly after the LIBOR debacle is sorted, ensuring a bit of good press in the wake of bad.

The bottom line
Look, go for it. Why not invest in RBS and just hold on for the ride? At some point, the share price is going to go up. Not only does the government want it to, the share price also happens to form a 25% chunk of the executive directors' long-term incentive plan . If that combination isn't enough to get the price up, then nothing is. As I see it, for long-term investors, RBS is pretty fool-proof, if only because of the weakness of the system that oversees it. 

Fool contributor Andrew Marder owns shares of Barclays. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.