Q: can any court anywhere in the us skip arraignment preliminary and pre trial hearings and go straight to trial?

A: I'll only speak to Maryland since that is where you appear to be located. For crimes prosecuted in The district Court of Maryland, the only court date is typically the trial date. Any pretrial motions are addressed on the day of trial.

A: Arraignment is simply the formal notice to the defendant of the charges against him or her before a judicial officer, and may or may not require the defendant to enter a plea (typically, not guilty at that stage). Formal arraignment is not constitutionally required, and is a matter of local procedural practice. A preliminary hearings is a proceeding before a judge where the government presents its basis for probable cause in support of the charges, and it is also not constitutionally required, but is a matter subject to local procedural rules. A pre-trial hearing can be for many purposes--to schedule future hearing dates (like motions hearing, trial, etc.), or to enter a plea, or to consider other matters raised by the parties--and is essentially for the orderly management of the court's docket and the time deadlines for the particular case. Different offenses require different procedural rules and safeguards, so that serious felonies that require a grand jury indictment to commence a prosecution typically have all three of these proceedings. They're purpose is to ensure not only that the prosecution proceeds in an orderly fashion, but that the defendant is afforded adequate procedural Due Process. However, more minor cases, like those typically prosecuted in the District Court in Maryland, will not involve any of these pre-trial proceedings, and the defendant's first appearance can be at trial. For defendants who were arrested and taken before a District Court Commissioner for initial release on bond, they are arraigned before the Commissioner. For defendants in jailable criminal offenses who were issued criminal citations or were mailed a criminal summons, they are typically directed to appear at a Preliminary Inquiry, where arraignmenent takes place. A defendant may request a postponement if they are appearing before a judicial officer for the first time on the date of trial. What you are really asking has to do with the minimum requirements of procedural and substantive due process required by the Constitution, and there are no pre-set hearing requirements mandated under the Constitution for all criminal prosecutions.