Can a defendant challenge the truthfulness of an affidavit supporting a search warrant?

A defendant may challenge the truthfulness of statements made in an affidavit supporting a search warrant only if he "makes a substantial preliminary showing that a false statement knowingly and intentionally, or with reckless disregard for the truth, was included by the affiant in the warrant affidavit, and if the allegedly false statement is necessary to the finding of probable cause." Franks v. Delaware, 438 U.S. 154, 156 (1978). If the defendant fails to make this "substantial preliminary showing," the evidence seized pursuant to the warrant will not be suppressed. See id., 438 U.S. at 171.