An invalid contract is not protected by this clause.1 Thus a contract which is illegal,2 or without consideration,3 or indefinite,4 or ultra vires,5 or where conditions precedent have not been complied with, as where certain franchises were to vest when electric light works were put into successful operation and this was never done,6 or where the necessary consent of the city authorities was never obtained,7 is not protected against impairment by subsequent legislation. So an unconstitutional statute,8 or ordinance,9 cannot confer contract rights within the protection of this clause.10

4 State's Prison v. Day, 124 N. C. 362; 46 L. R. A. 295; 32 , S. E. 748; Hoke v. Henderson, 15 N. C. 1; 25 Am. Dec. 677.

5 State v. Wilson, 121 N. C. 425, 480; 61 Am. St. Rep. 672; (opinion in 61 Am. St. Rep. 672 not on this point), 28 N. E. 554.

6 Mial v. Ellington, 131 N. C. 134; 46 S. E. 961.

7 Butler v. Commonwealth, 10 How. (U. S.) 402; Moores v. State, - Neb. - ; 93 N. W. 733; Ex parte Lawrence, 1 0. S. 431.

8 People v. Coler, 173 N. Y. 103; 65 N. E. 956.

9 New York v. Squire. 145 U. S. 175; Isenberg v. Selvage. 103 Ky. 200; 44 S. W. 974; Shotwell v. Ry.,

69 Miss. 541; 11 So. 455; Nye v. Ross, 17 R. I. 733; 16 L. R. A. 798; 24 Atl. 777.

1 Folsom v. Ninety-Six Township, 59 Fed. 67.

2 Durkee v. People, 155 111. 3.14; 46 Am. St. Rep. 340; 40 N. E. 626. As where it is usurious. Hardin v. Trimmier, 27 S. C. 110; 3 S. E. 46. Or where an assignment to evade ex-emption laws is forbidden by statute. Bishop v. Middleton. 43 Neb. 10; 26 L. R. A. 445; 61 N. W. 129.

3 Louisiana v. New Orleans, 109 U. S. 285; Lord v. Litchfield. 36 Conn. 116; 4 Am. Rep. 41; Hardy v. Waltliam. 7 Pick. (Mass.) 110; State v. Gilmore, 141 Mo. 506; 42