Election Investigations Guidebook In common law countries with constitutional protections against unreasonable searches and seizures, election investigators may need to obtain a warrant before collecting evidence. In Canada, for example, the Special Investigators’ Manual emphasizes that investigators cannot compel the production of documentary evidence without a court order.162 As a result, this manual includes extensive directions for obtaining a search warrant.163 Unlike Canada, however, the vast majority of states do not currently provide any guidance for election investigators about possible search and seizure requirements nor how they might apply to different types of violations or offenses. In many legal systems, if an investigator secures evidence in an unacceptable manner, the adjudicative body can later exclude this evidence from consideration even if it provides conclusive proof of guilt or wrongdoing.164 By failing to collect the evidence correctly, an investigator can compromise the primary purpose behind an election investigation, which is to provide the adjudicator with reliable, substantiated information that can contribute to the impartial resolution of an electoral dispute. Conducting Interviews Interviews allow investigators to clarify and corroborate evidence, which facilitates reaching a final decision based on an objective assessment of the facts. Eyewitness interviews can also serve as a source of evidence in a case. As the Uniform Guidelines on Investigations note, “interviews of witnesses” are one important avenue for verifying evidence.165In El-Masri v. the Former Yugoslav Republic of Macedonia, the European Court of Human Rights agreed that the collection of evidence during an investigation should include testimony from eyewitnesses.166 At the same time, the Canadian Special Investigators’ Manual also acknowl- 162 See Canadian Investigators’ Manual Ch. 8, supra note 146, at 4. 163 See generally id. appendices 4–5. 164 In the United States, this principle is known as the “exclusionary rule”; in Germany, Beweisverwertungsverbote (prohibitions on the use of evidence); and in Italy, inutilizzabilità (non-usability). See generally Ius Gentium: Comparative Perspectives on Law & Justice, Exclusionary Rules in Comparative Law (Stephen C. Thaman ed., 2013) (examining the national and international human rights dimensions of exclusionary rules in various civil and common law countries). 165 Uniform Guidelines 2009, supra note 25, ¶ 34 (emphasis added). 166 El-Masri v. Former Yugoslav Republic of Macedonia, App. No. 39630/09, 2012-VI Eur. Ct. H.R. 263, ¶ 183 (2012), http:// hudoc.echr.‌coe.‌int/‌sites/eng/pages/search.aspx?i=001-115621. Id. 68