The Northeast, once the nation’s political engine that produced presidents, House speakers and Senate giants including the late Edward M. Kennedy, is losing clout in Washington as citizens flee the high-tax region, according to experts worried about the trend.

The Census Bureau reports that population growth has shifted to the South and the result is that the 11 states that make up the Northeast are being bled dry of representation in Washington.

Critics blame rising taxes in states such as Massachusetts and Connecticut for limiting population growth in the Northeast to just 15 percent from 1983 to 2013, while the rest of the nation grew more than 41 percent.

The biggest impact comes in the loss of congressional representation.

Deep in a recent report, for example, the American Legislative Exchange Council tabulated how the drop in population relative to the rest of the nation cut the region’s power in Washington. While the states from Pennsylvania to Maine had 141 House members in 1950, they are down to 85 today, a drop of some 40 percent.