Police The power to pass ordi nances for the protection of the public health, safety, morals and general welfare of the mu nicipality is commonly conferred upon cities by express grant. It may be implied, however, from a general grant of power to pass ordi nances. It is under this authority that munici palities make enactments relative to the preser vation of peace and order, sanitation, fire pro tection, regulation of amusements and occupa tions and the control of vice. When exercised by the city the police power is subject to all the usual constitutional restraints against arbi trary and discriminatory enactments, and in addition police ordinances are held void if they are unreasonable even though they violate no constitutional clause. The city is incapable of parting with its police power by the making of any grant, concession, exemption or contract. Its police ordinances may deal with subjects already covered by State law provided the ordi nance does not conflict with the statute. The power to pass police ordinances carried with it by implication the authority to establish and enforce reasonable penalties. Such ordinances may be enforced either by penalties inflicted upon individuals or by summary destruction of private property which is held to be a public nuisance.
Municipal The power to make contracts is given to all municipalities by ex press grant or by implication. Such contracts have the same general legal character as con tracts between individuals but the city must be exceedingly cautious not to exceed its power. If the procedural requirements in the city char ter are not complied with the contract is void.
Where cities enter into contracts for the secur ing of services or goods it is commonly re quired that the city must call for sealed bids based upon plans and specifications and that the contract must be let to the lowest respon sible bidder. If it can be clearly shown that a city did not have the requisite authority to make a given contract such a contract is com pletely void. Cities are, however, bound by the principles of common honesty and in cases where its contracts are illegal because of hidden defects of procedure or non-compliance with other formal requirements the city may still be bound. It may elect to ratify such contracts and ignore the irregularities, or, under what is known as the doctrine of estoppel, it may be prevented by the courts from setting up its own illegal acts for the purpose of freeing it self from its just obligations. The contracts of a municipality are enforceable in court like other contracts and neither the city nor the State legislature may by ordinance or statute impair their obligation.
Miscellaneous American municipality enjoys several powers which do not call for elaborate discussion. It may ap propriate and spend money for purposes within its authority and in accordance with the pro cedure outlined in its charter. It may, within these same limits, acquire, manage and dispose of property.. It may construct public improve ments and in so doing may use the power of eminent domain and levy special assessments. Its power to incur debts, own and operate public utilities and services and grant fran chises are treated in separate articles. See