Requirement to issue reasoned decision
Germany
Answer
Yes
Source
Law on the Scrutiny of Elections(Wahlpr?fungsgesetz), (published 1951-03-12, last amended 2012-07-12), http://www.bundeswahlleiter.de/en/bundestagswahlen/downloads/rechtsgrundlagen/wahlpruefungsgesetz_engl.pdf
Section 11
The decision of the Board must be recorded inwriting; it must propose a decision to the Bundestag. The Bundestag must decideon the validity of the contested election and on the consequences of declaringit invalid. If the rights of a person or a group of persons have been violatedin preparing or conducting the elections, this shall be established in thedecision. The decision must indicate the essential facts and reasons on whichthe decision is based. Because of the details, reference to the file contentsshall be permissible.