Why Can't Attorneys Guarantee Results in Criminal Cases?
Choosing the right attorney to defend against a pending criminal charge may be one of the most important decisions you'll ever need to make. Hiring a good attorney is also very expensive. Most expensive goods and services are available with some sort of warranty, so why can't criminal defense attorneys guarantee results?
If you've shopped around then you've probably spoken to lawyers who made educated guesses about what will happen in your case based on past experience with similar cases in the same jurisdiction. You may also have noticed that most of them are unwilling to guarantee that they'll get a criminal charge dismissed, even when they strongly believe that's what will happen. If you asked them for a guarantee, you probably heard that "no attorney can (ethically) guarantee a particular result," that there are "too many variables," that "every case is different" and so on.
Those statements are all true but they are also all true in other areas of law, e.g., personal injury cases, where lawyers DO offer guarantees. What's different about criminal law?

Contingent Fees Are Forbidden in Criminal Cases
A contingent fee (aka "contingency fee" or "conditional fee") is a fee that depends on a favorable result in a case. A simple example would be a lawyer promising to refund her fee if she doesn't succeed in getting a criminal case dismissed. Louisiana lawyers are prohibited from making such guarantees in criminal cases by Rule 1.5(d)(2) of the Louisiana Rules of Professional Conduct:

LOUISIANA RULES OF PROFESSIONAL CONDUCT
I. CLIENT-LAWYER RELATIONSHIP
Rule 1.5(d)(2) Fees
  • (d)A lawyer shall not enter into an arrangement for, charge, or collect:
(2)a contingent fee for representing a defendant in a criminal case.

How Does Rule 1.5(d)(2) Protect Consumers?
Why would a drought-stricken farmer pay a shyster good money to do a rain dance? Out of desperation. Similar dynamics apply here. People facing serious criminal charges often feel a level of anxiety that leaves them vulnerable to being scammed. They are desperate for a savior and willing to pay (anything in some cases) for an attorney's promise to make it go away. Unfortunately, unethical attorneys are willing to take advantage of that desperation by making promises that they can't possibly keep.
Rule 1.5(d)(2) protects consumers by prohibiting lawyers from making promises that they don't actually have the power to keep, such as whether a criminal case is ultimately dismissed, just to get hired on a case.

Wouldn't a Contingent Fee Motivate an Attorney To Obtain a Favorable Result for the Consumer?
Not necessarily. In the real world, each lawyer represents multiple clients and has many demands competing for her time and attention. An attorney has an ethical duty to diligently represent each and every one of her clients but being diligent and prepared in every case is not always easy.
Now consider that an attorney's fee is significantly higher for some cases than for others based on various factors. For example, the attorney might have one client that paid $10,000 for representation in a felony case while another client paid $3,000 for a misdemeanor. If contingent fees were allowed, there would be an obvious financial incentive to neglect lower-paying cases in favor of those with higher fees.
Even worse, contingent fees could make it profitable for an unethical defense attorney to conspire with an unethical prosecutor to sacrifice lower paying clients in favor of higher-paying clients. The prohibition on guaranteed results removes that inappropriate incentive.

What's Wrong With Hiring An Unethical Attorney?
A lawyer who violates the rules of ethics does it to help himself, not his clients.
Beware the criminal defense attorney who claims that you will get special treatment as her client because she has a special relationship with a judge or prosecutor. That is highly unethical conduct and is probably dishonest as well. It is much more likely that the attorney is lying to convince you to hire him. Chances are that such an attorney will wait until later (when you are no longer in a good position to hire a different attorney) to offer a pat excuse for failing to deliver. If you complain, he will claim that that you misunderstood or even that you are lying.
In some situations, hiring an unethical attorney may seem like the best way to "win" a case, but that route is actually more likely to result in you getting burned than in you achieving a better outcome for your case. Most attorneys--even unethical ones--are unwilling to risk their law licenses to obtain better results for their clients.
You need to be able to trust that your attorney is being honest with you if he says you have a good chance of winning at trial. An unethical attorney may have a hidden agenda, such as getting you to pay an additional fee to try your case. Likewise, if your attorney recommends that you accept a plea bargain offer, you need to be confident that he isn't acting out of self-interest, such as avoiding the hard work and diligent preparation that may be necessary to get a better result.
In other words, there will probably come a time during the representation when, unbeknownst to you, your interests and those of your attorney are not perfectly aligned. When that happens, the unethical attorney will act in his own best interest rather than yours.

My Guarantee
As an ethical attorney, I cannot promise a specific result but I can and do give my clients my honest opinion about the most likely outcome in their cases. I believe that the only way to consistently get great results is to diligently prepare each and every case. I intentionally keep a small caseload so that I have sufficient time to personally work on all of my clients' cases.
When I become your attorney, I will work hard to ensure the best possible outcome in your case. I will look for defenses and problems with the government's case against you. I will ultimately know more about the government's case than the prosecutors do and will use every weakness to your advantage. I will keep you updated regarding the progress of your case. I will answer the phone myself when possible and will do my best to respond to your telephone messages by the end of the next business day at the latest.
I will limit the number of court appearances you are required to attend when possible. I will attempt to negotiate the best possible pre-trial resolution but will not pressure you into accepting a plea bargain offer. In any case where the punishment range includes jail time, I will not charge a separate trial fee. This will ensure that you can accept or reject the government's offer on its merits alone rather than feeling pressured to accept a plea bargain agreement just to avoid an expensive trial fee.
Finally, if you have a question or issue that should be addressed by a lawyer in a different practice area, such as professional licensing, immigration, or divorce, I will refer you to a qualified individual in that practice area rather than pretending to an expertise that I do not have.

Isn't It Unethical to Defend Someone Who Is Guilty?
Absolutely not. It is actually unethical for a lawyer to be less diligent in representing a client because the lawyer believes the client is guilty.
People often use "ethics" and "morals" interchangeably in everyday conversation. Both words are related to concepts of right and wrong but they have different meanings in the context of a lawyer's conduct. Professional ethics, as discussed above, are dictated by a single
set of rules that governs the professional conduct of all Louisiana lawyers. Morals, on the other hand, are personal principals that are unique to an individual and guide his or her behavior in all spheres, both personal and professional. I am not even remotely troubled by representing a person who is guilty.