Criminal law is based upon constitutional law. Law enforcement agents extensively rely upon scientific principles and technology in criminal prosecutions. All cases involving criminal charges generally entail some aspect of scientific evidence and forensic science. Forensic science is used to convict the guilty and to protect and exonerate the innocent. It is the most persuasive evidence. The Due Process Clause, Confrontation Clause and the Sixth and Fourteenth Amendments of the United States Constitution require attorneys to adequately understand scientific principles for litigation of forensic science issues. The Sixth Amendment states, “[i]n criminal prosecutions the accused a person shall . . . have the Assistance of Counsel for his defense.” The right to counsel is applicable to state jurisdictions through the 14th Amendment, established via Faretta v. California 422 U.S. 806 (1975).

The Supreme Court revised the standards for admissibility of scientific evidence and expert witness testimony through the seminal cases of Daubert, Joiner and Kumho Tire. The controversial issues of reliability, peer review, error and uncertainty rates, and standardization still adversely affect competent use of forensic science.

The reliance on forensic sciences in criminal cases has increased substantially in recent years through advancing technology, thereby fostering oversight of the scientific evidence used in criminal cases. A nationwide movement has emerged advocating investigation, research and improvement of scientific methods in forensics. This sentiment is perpetuated by the discovery of flawed forensics, high-profile crime laboratory scandals, fraud, wrongful convictions, as well as the exposure of junk sciences and issuance of the National Academy of Sciences (NAS) report in 2009. 

The reports

On September 16, 2016, the President’s Council of Advisors on Science and Technology (PCAST) released its report, “Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature-Comparison Methods,” condemning problems endemic in forensic science disciplines and recommending standards to validate forensic methods, training forensic examiners and making forensic laboratories independent of police and prosecutors. The NAS and PCAST reports poignantly discussed the legal profession’s failings concerning scientific evidence, including “a lack of statistical rigor to justify stating results, or repeated and objective testing to ascertain an ability to reliably produce results at all.”1

In response to the NAS report, the government established the National Commission of Forensic Science (NCFS) in 2013. The NCFS recommended all forensic techniques should be independently validated before being used in criminal investigations. Proclaiming evidence is “scientific” does not make it so.2 Scientific validity and reliability are not determined or equated by conviction rate. These reports and findings are an inconvenience to law enforcement and prosecutors. 

The Department of Justice (DOJ), through former Attorney General Loretta Lynch, rejected the PCAST report. AG Lynch declared the DOJ would not adopt the recommendations relating to admissibility of forensic science. The FBI stated PCAST made erroneous and overbroad assumptions. 

On April 10, 2017, Attorney General Jeff Sessions ordered the DOJ to end the NCFS and suspend FBI review policy. Accordingly, scientific standards are to be determined by the DOJ. U.S. District Judge Jed S. Rakoff of New York, the only federal judge on the commission, said, “It is unrealistic to expect that truly objective, scientifically sound standards for the use of forensic science ... can be arrived at by entities centered solely within the Department of Justice.” Forensic science evidence continues to be admitted, with and without critical judicial evaluation by courts.3

Effective representation

The Sixth Amendment and Due Process Clause are emerging as sources of regulation to increase the reliability and validity of scientific evidence and competency of counsel. The courts have sought to create workable standards to assist litigators in admitting and using forensic sciences during trial. A constitutional difference exists between admitting the expert’s opinion and using the expert to introduce the underlying report from a third party as a basis to form an opinion.4 Furthermore, use of false evidence, debunked sciences, or repudiated expert witness opinions is a basis for challenging a conviction through a writ of habeas corpus and new trial.5 Rules governing expert witness qualifications, however, lack specificity and discernable standards despite the courts’ attempt to stay current with the rapid advancements in forensic science.

Developments in forensic science have prompted the Supreme Court to issue decisions increasing counsel’s duty to competently litigate forensic science evidence. The standard for effective attorney representation is whether the performance was deficient, and errors existed depriving a person of fair trial (e.g., but for the attorney’s conduct, there would be a different result).6 This obligation requires a working knowledge of forensic science. Attorneys still lack a fundamental understanding of scientific issues, which impedes effective and competent representation. The inability of counsel to adequately vet scientific evidence through cross-examination has led courts to place considerable dependence on sound laboratory techniques, careful litigation, complete disclosure of scientific procedures, scientific methodologies, and the limitations of forensic evidence. Most of these decisions are made at the trial court level on a case-by-case basis.

Unfortunately, the “courts continue to rely on forensic evidence without fully understanding and addressing the limitations of different forensic science disciplines,” as stated in the NAS report.  
Scientific developments, societal sophistication, and court decisions have strengthened the obligation of counsel to litigate forensic science evidence. Attorneys must improve their understanding of forensic science to competently represent their clients in accordance with constitutionally mandated principles of due process and confrontation. 

Works Cited
1.    Roderick T. Kennedy, Stare Decisis Is Not Scientific, The SciTech Lawyer, vol.13, no.4, p.8, 9 (Summer 2017)
2.    Sunita Sah, Arturo Casadevall, Suzanne Bell et al, We Must Strengthen the “Science” In Forensic Science, Scientific American, May 8, 2017.
3.    Kennedy, Stare Decisis Is Not Scientific, The SciTech Lawyer, supra.
4.    Crawford v. Washington, 541 U.S. 36 (2004); Melendez-Diaz v. Massachusetts, 557 U.S. 305 (2009); Bullcoming v. New Mexico, 564 U.S. 647 (2011); Williams v. Illinois, 564 U.S. 50 (2012).
5.    Calif. Penal Code, Title 12, Chpt. 1, Sect. 1473 Writ of Habeas Corpus, eff. Jan. 1, 2015 (2016); Texas Code of Criminal Procedure, Chpt. 11, Art. 11.073, eff. Sept. 1, 2013 (2016) Habeas - Procedures related to certain scientific evidence (The Junk Science Writ). 
6.    The right to counsel is the right to effective assistance of counsel. Strickland v. Washington, 466 U.S. 668 (1994); Maryland v. Kulbicki, 136 S.Ct. 2, 577 U.S. 
_ (2015). 
This article is adapted from Natalie Arvizu and Gil Sapir, Constitutional Requirement To Litigate Scientific Evidence, American Academy of Forensic Sciences Proceedings, Vol. 23, p. 834 (2017).

Natalie Arvizu, JD, is a law clerk for New Mexico Appellate Court. She may be contacted at New Mexico Court of Appeals, 2211 Tucker, NE, Albuquerque, N.M. 87125. Gil Sapir, JD, MSc, is a forensic science consultant and attorney. He may be contacted at PO Box 6950, Chicago, Ill. 60680