Understanding DWI Charges and Your Fourth Amendment Rights

If you’ve been charged with DWI in Texas, understanding how the Fourth Amendment protects you is critical to defending your rights.

Key Takeaways:

• The Fourth Amendment protects you from unreasonable searches and seizures, which often come into play during DWI stops.
• Police must have reasonable suspicion to stop your vehicle and probable cause to arrest you for DWI.
• A strong legal defense often centers on whether your constitutional rights were violated during the traffic stop, search, or arrest.

Facing DWI charges can be one of the most stressful moments of your life. A traffic stop that begins with flashing lights in your rearview mirror can quickly escalate into an arrest, criminal charges, and the possibility of harsh penalties. Understanding your legal rights in these situations is essential to protecting your freedom and future.

At The Medlin Law Firm, we have more than 85 years of combined experience and over 2,500 case wins defending Texans against criminal charges. Our team is passionate about justice, and as board-certified criminal law attorneys, we know the system inside and out. In this blog, we’ll break down how the Fourth Amendment applies to DWI cases in Texas, what protections it provides, and how we use it to build strong defenses for our clients.

What the Fourth Amendment Protects

The Fourth Amendment to the U.S. Constitution guarantees protection against unreasonable searches and seizures. In everyday terms, this means the police cannot stop, search, or arrest you without a valid reason.

In DWI cases, this protection is critical because the legality of a stop or arrest often determines whether the evidence against you can be used in court. If officers violated your Fourth Amendment rights, your attorney may be able to have key evidence—such as breathalyzer results or field sobriety tests—thrown out.

Reasonable Suspicion and Traffic Stops

The first step in most DWI cases is the traffic stop. Police must have what’s known as “reasonable suspicion” to pull you over, meaning they must observe something that suggests you may be violating the law, such as:

• Swerving between lanes
• Driving unusually slowly or erratically
• Running a stop sign or traffic light
• Failing to use turn signals

If an officer stops you without a valid reason, the stop may be illegal. Evidence gathered after an unlawful stop could be challenged in court. This scenario is one of the most common ways the Fourth Amendment plays a role in DWI defense.

Probable Cause for Arrest

Reasonable suspicion allows an officer to pull you over, but it is not enough to arrest you. To take that next step, the officer must have probable cause—a higher standard of evidence.

Probable cause in a DWI case may come from:

• Observing signs of intoxication, like slurred speech or bloodshot eyes
• Failing field sobriety tests
• Breath or blood test results suggesting a blood alcohol concentration (BAC) above the legal limit

If the officer cannot demonstrate probable cause, your arrest may be unconstitutional. An experienced criminal defense lawyer will carefully examine the details of your arrest to determine if probable cause truly existed.

Searches and the Fourth Amendment

Beyond traffic stops and arrests, the Fourth Amendment also comes into play with searches. In DWI cases, searches often involve:

• Vehicle searches: An officer typically needs probable cause or your consent to search your car. Evidence found during an unlawful search may be inadmissible in court.
• Blood tests: In most cases, police need either your consent or a warrant to take a blood sample. There are exceptions, but the Supreme Court has limited when warrantless blood draws are permissible.

If your vehicle was searched or your blood was taken without following the proper legal procedures, your rights may have been violated. A violation of your rights could lead to evidence being suppressed, significantly weakening the prosecution’s case.

Field Sobriety and Chemical Tests

Field sobriety tests, such as walking in a straight line or standing on one leg, are used by officers to establish probable cause. However, these tests are subjective and can be influenced by medical conditions, fatigue, or even nervousness.

Breath and blood tests are more technical, but they are not foolproof. Machines may be improperly calibrated, tests may be administered incorrectly, or samples may be mishandled. Challenging these tests is often part of a strong DWI defense, especially when Fourth Amendment issues are involved.

Common Fourth Amendment Issues in Texas DWI Cases

Some of the most frequent constitutional problems we see in DWI cases include:

• Traffic stops made without reasonable suspicion
• Arrests conducted without probable cause
• Unlawful searches of vehicles
• Blood draws taken without consent or a valid warrant
• Evidence collected in violation of proper procedures

When these issues are present, it can dramatically change the outcome of a case. A successful Fourth Amendment challenge may result in evidence being thrown out, charges reduced, or even a full dismissal.

The Medlin Law Firm: Fighting for Justice in Texas

Defending against a DWI is all about knowing how to apply the law. Our skilled Texas DWI attorneys at The Medlin Law Firm will investigate every detail of your stop, arrest, and testing procedures to identify whether your rights were violated.

A DWI conviction in Texas can lead to serious consequences: jail time, fines, license suspension, higher insurance rates, and a permanent criminal record. These consequences can follow you for years, impacting your career, family, and reputation.

We approach each case with the mindset that the prosecution must prove its case beyond a reasonable doubt. By focusing on constitutional protections, we create opportunities to weaken the state’s evidence and fight for the best possible outcome for our clients.

The good news is that being charged with DWI is not the same as being convicted. With the right defense strategy, The Medlin Law Firm can help you fight back, and the Fourth Amendment often provides the foundation for that defense.

At The Medlin Law Firm, we believe every client deserves a passionate defense. With more than 85 years of combined experience, 2,500 case wins, and board certification in criminal law, our team has the knowledge and dedication needed to stand up for your rights. Contact us today to schedule a free case evaluation and take the first step toward protecting your future.