Wis. Stat. § 971.12
If 2 defendants were charged and the cases consolidated, and one then pleads guilty, there is no need for a severance, especially if the trial is to the court. Nicholas v. State, 49 Wis. 2d 678, 183 N.W.2d 8 (1971). Severance is not required if the 2 charges involving a single act or transaction are so inextricably intertwined so as to make proof of one crime impossible without proof of the other. Holmes v. State, 63 Wis. 2d 389, 217 N.W.2d 657 (1974). Due process of law was not violated, nor did the trial court abuse its discretion, by denying the defendant's motion to sever 3 counts of sex offenses from a count of first-degree murder. Bailey v. State, 65 Wis. 2d 331, 222 N.W.2d 871 (1974). In a joint trial on charges of burglary and obstructing an officer, while evidence as to the fabrication of an alibi by the defendant was probative as to the burglary, the substantial danger that the jury might employ the evidence as affirmative proof of the elements of that crime, for which the state was required to introduce separate and independent evidence showing guilt beyond a reasonable doubt, required the court to administer a clear and certain cautionary instruction that the jury should not consider evidence on the obstructing count as sufficient in itself to find the defendant guilty of burglary. Peters v. State, 70 Wis. 2d 22, 233 N.W.2d 420 (1975). Joinder was not prejudicial to the defendant moving for severance when the possibly prejudicial effect of inadmissible hearsay regarding the other defendant was presumptively cured by instructions. State v. Jennaro, 76 Wis. 2d 499, 251 N.W.2d 800 (1977). If a codefendant's antagonistic testimony merely corroborates overwhelming prosecution evidence, refusal to grant severance is not an abuse of discretion. Haldane v. State, 85 Wis. 2d 182, 270 N.W.2d 75 (1978). Joinder of charges against the defendant was proper when separate acts exhibited some modus operandi. Francis v. State, 86 Wis. 2d 554, 273 N.W.2d 310 (1979). The trial court properly deleted implicating references from a codefendant's confession rather than granting the defendant's motion for severance under sub. (3). Pohl v. State, 96 Wis. 2d 290, 291 N.W.2d 554 (1980). The trial court did not abuse its discretion in denying a severance motion and failing to caution the jury against prejudice when 2 counts were joined. State v. Bettinger, 100 Wis. 2d 691, 303 N.W.2d 585 (1981). Joinder is not prejudicial when the same evidence would be admissible under s. 904.04 if there were separate trials. State v. Hall, 103 Wis. 2d 125, 307 N.W.2d 289 (1981). The trial court abused its discretion in denying a motion for severance of codefendants' trials when the movant made an initial showing that his codefendant's testimony would have established his alibi defense and his entire defense was based on the alibi. State v. Brown, 114 Wis. 2d 554, 338 N.W.2d 857 (Ct. App. 1983). Joinder under sub. (2) was proper when two robberies were instigated by one defendant's prostitution and the other defendant's systematic robbing of customers who refused to pay. State v. King, 120 Wis. 2d 285, 354 N.W.2d 742 (Ct. App. 1984). Misjoinder was harmless error. State v. Leach, 124 Wis. 2d 648, 370 N.W.2d 240 (1985). To be of "the same or similar character" under sub. (1), crimes must be of the same type, occur over a relatively short time period, and evidence as to each must overlap. State v. Hamm, 146 Wis. 2d 130, 430 N.W.2d 584 (Ct. App. 1988). If an appellate court vacates a conviction on one or more counts when multiple counts are tried together, the defendant is entitled to a new trial on the remaining counts upon showing compelling prejudice arising from evidence introduced to support the vacated counts. State v. McGuire, 204 Wis. 2d 372, 556 N.W.2d 111 (Ct. App. 1996), 95-3138. A violation of sub. (3) does not require a new trial in all cases but is subject to harmless error analysis. State v. King, 205 Wis. 2d 81, 555 N.W.2d 189 (Ct. App. 1996), 95-3442. Simultaneous trials of 2 defendants before 2 juries is permissible. An impermissible confession in one case not heard by the jury in that case accomplishes the required severance of the cases. State v. Avery, 215 Wis. 2d 45, 571 N.W.2d 907 (Ct. App. 1997), 96-2873. For severance to be granted, it is not sufficient to show that some prejudice was caused. Any joinder of offenses is apt to involve some element of prejudice to the defendant, since a jury is likely to feel that a defendant charged with several crimes must be a bad individual who has done something wrong. However, if the notion of involuntary joinder is to retain any validity, a higher degree of prejudice, or certainty of prejudice, must be shown before relief will be in order. State v. Linton, 2010 WI App 129, 329 Wis. 2d 687, 791 N.W.2d 222, 09-2256. Subsection (1) is broadly construed in favor of initial joinder. The court has historically favored initial joinder particularly when the charged crimes were all committed by the same defendant. State v. Salinas, 2016 WI 44, 369 Wis. 2d 9, 879 N.W.2d 609, 13-2686. In assessing whether separate crimes are sufficiently "connected together" for purposes of initial joinder under sub. (1), the court looks to a variety of factors, including: 1) are the charges closely related; 2) are there common factors of substantial importance; 3) did one charge arise out of the investigation of the other; 4) are the crimes close in time or close in location, or do the crimes involve the same victims; 5) are the crimes similar in manner, scheme, or plan; 6) was one crime committed to prevent punishment for another; and 7) would joinder serve the goals and purposes of this section. State v. Salinas, 2016 WI 44, 369 Wis. 2d 9, 879 N.W.2d 609, 13-2686. Joinder and severance. 1971 WLR 604.