regarded with the same effect as a decision upon any other fact issue submitted for judicial determination. But an inquiry and determination there must always be.
A court is bound to take notice of the limits of its authority. It is its right and duty to make an examination into its jurisdiction, whether raised by the pleadings or suggested by counsel or not, and to determine its power to entertain the cause. If the court finds at any stage of the proceedings that it is without jurisdiction, it is its duty to take proper notice of the defect by staying the proceedings, dismissing the cause, or by other appropriate action. East Side Baptist Church v. Morgan, 204 Okl. 685, 233 P.2d 957, 958; Alexander Drug Co. v. Holbert, 156 Okl. 198, 10 P.2d 412; Fehr v. Black Petroleum Corporation, 103 Okl. 241, 229 P. 1048, 1050, 21 C.J.S. Courts § 114, pp. 175, 176.
When constitutionally protected rights are at stake, the court’s determination of the validity of its process must be made, at the latest, when the judgment is rendered and before it is sought to be enforced or vacated. Due process is violated by the mere act of exercising judicial power upon process not reasonably calculated to apprise the defendant of the pen-dency of an action. Riverside & Dan River Cotton Mills v. Menefee, 237 U.S. 189, 35 S.Ct. 579, 59 L.Ed. 910. And the violation is not cured by granting the aggrieved party a hearing on his motion to set aside the tainted judgment. The burden of affording proper notice rests on the plaintiff. It cannot be avoided by the perfunctory judicial approval of an unsupported conclusion of “due diligence”. Armstrong v. Manzo, 380 U.S. 545, 85 S.Ct. 1187, 14 L. Ed.2d 62.
Our practice and procedure are not conducive to the conduct of an inquiry into the issue of due diligence prior to the rendition of a default judgment in a case in which resort was had to publication process. While the terms of 12 O.S.1961, § 174 provide that “[n]o judgment by default shall be entered on [publication] service until proof thereof be made, and approved by the court * the statute does not expressly require that an inquiry into plaintiffs due diligence be conducted. It merely provides that the instruments comprising publication process and proof thereof shall be examined and approved. Washburn v. Culbertson, 181 Okl. 476, 75 P.2d 190, 193.
In some states in which an order for publication service is required before process by publication may be effected, such order may not be made unless the judge is satisfied that the plaintiff has in fact exercised due diligence to ascertain the names and residences of defendants before resorting to constructive service. Sheffield v. Carter, Fla.App., 141 So.2d 780, 786. While this appears to be a safer practice, our present statute contains no similar requirement. The provisions of our Children’s Court Act, 20 O.S.1961, § 886, do, however, contemplate a pre-publication inquiry and an order authorizing publication notice. We held in Copas v. Reents, Okl., 365 P.2d 983, 986, that an order authorizing publication process after finding personal service “impracticable” was essential. The reason for a judicial inquiry into due diligence and a determination of its existence, as required by the provisions of the Children’s Court Act, is equally critical in other civil actions.
Our decisional law, as it now stands, does not reflect the apparent reasons underlying the 1953 amendment to 12 O.S. 1951, § 171. Nor does it provide a proper mechanism for a meaningful judicial determination of due diligence from probative facts as distinguished from the pleader’s sworn conclusion of its existence. Jurisdictional facts can not be rested on such a frail basis. The present procedure makes it possible for a plaintiff to procure a default judgment on publication process solely upon his own, or his counsel’s, sworn declaration of a pure legal conclusion and without disclosing the pertinent facts. This, in its effect, amounts to a method of sanctifying self-declared land claims by in