Which constitutional principle allows the national government to have an impact on state-level civil rights violations under the civil rights act of 1964?

The constitutional principle which might have inspired the Civil Rights Bill of 1964, enacted on July 2nd, of the same year is that of egalitarianism, particularly regarding equal treatment for citizens before the law -14th Ammendment-, and the right to vote -15th Ammendment-,   because all the provisions in this ruling address the prohibition to discriminate people  based on race, color, religion, sex or national origin, specially when regulating labor relations and the right to vote.

The Supreme Court therefore,has the authority to rule over those civil rights violations which took place at a state level,  and so they did, for example, in 1974, ruled that the San Francisco school district had violated the students´ rights as they did not have separate classes for non-English speakers, mixing students in the same classrooms, because  notall the students were ultimately being treated equeally before the law.    

the captain of a steam ship naturally chooses the shortest route to his destination. since a sailing ship is usually pushed by winds and currents, its captain must find a route where the wind will probably blow in the right direction. tacking, i.e. using contrary wind to pull (sic) the sails, was always possible but wasted time because of the zigzagging required, and this would significantly delay long voyages. the early european explorers were not only looking for new lands. they also had to discover the pattern of winds and currents that would carry them where they wanted to go. during the age of sail winds and currents determined trade routes and therefore influenced european imperialism and modern political geography. for an outline to the main wind systems see global wind patterns.

pilotage or cabotage, in one sense, is the art of sailing along the coast using known landmarks. navigation, in one sense, is the art of sailing long distances out of sight of land.[1] although the polynesians were able to sail the pacific (with great difficulty) and people regularly sailed north and south across the mediterranean, before the time of columbus nearly all sailing was coastal pilotage

        it is some were in here? ///

the authority to tax.