In Virginia, "an accused may plead not guilty, guilty or nolo contendere." Code 19.2-254. The right of an accused to enter a nolo contendere plea, "a plea of guilty without an express admission of guilt, was firmly established in North Carolina v. Alford, 400 U.S. 25, 91 S. Ct. 160, 27 L. Ed. 2d 162 (1970)." Smith v. Commonwealth, 27 Va. App. 357, 361, 499 S.E.2d 11, 13 (1998). Code 19.2-254 also permits an accused charged with a felony, "with the approval of the court and the consent of the Commonwealth," to enter a conditional plea of guilty which preserves the right of the accused to "appeal . . . the adverse determination of any specified pretrial motion." Code 19.2-254. However, an ordinary guilty plea which is voluntary and intelligent constitutes "'a waiver of all defenses other than those jurisdictional . . . . Where a conviction is rendered upon such a plea and the punishment fixed by law is in fact imposed in a proceeding free of jurisdictional defect, there is nothing to appeal.'" Savino v. Commonwealth, 239 Va. 534, 539, 391 S.E.2d 276, 278 (1990). Thus, a guilty plea waives all preceding non-jurisdictional defects, including constitutional claims, Terry v. Commonwealth, 30 Va. App. 192, 197, 516 S.E.2d 233, 235-36 (1999) (en banc), and an Alford plea "'has the same preclusive effect as a guilty plea'" for purposes of appeal, Perry v. Commonwealth, 33 Va. App. 410, 412, 533 S.E.2d 651, 652-53 (2000) (quoting Cortese v. Black, 838 F. Supp. 485, 492 (D. Colo. 1993)); see Clauson v. Commonwealth, 29 Va. App. 282, 294, 511 S.E.2d 449, 455 (1999).