For Trump foes, Democratic gains may remain elusive in 2018

Passionate protests against Donald Trump's presidency have swelled the ranks of Democratic activists, but their new enthusiasm faces a hard reality:

In 2012, the first election under those new maps, Republicans won a 33-seat majority in the U.S. House even though Democratic candidates across the country received 1.4 million more votes than their Republican opponents.

"There are just more districts at the moment that have a natural tilt toward Republicans, partly because of Democratic geography and partly because of Republicans drawing districts with an eye toward helping pick up more seats for their party," said Michael Barber, an assistant political science professor at Brigham Young University who has studied the effects of gerrymandering and incumbency on congressional elections.

Former Attorney General Eric Holder recently signed on as chairman of the new National Democratic Redistricting Committee, which is attempting to better position Democrats for the 2021 redistricting by winning key statehouse races and court cases in the coming years.

The realities of the electoral map have tempered the optimism of some newly invigorated Democratic activists.

Since Election Day, Philadelphia physician Rhea Powell has marched with other women in Washington, protested in her home town against the potential repeal of Obama's health care law and joined in airport demonstrations against Trump's immigration restrictions.

"Politicians sometimes think that they made promises and their voters want them to keep them, but the historical pattern is the opposite — that public opinion moves against the direction of policy change," said political scientist Matt Grossmann, director of the Institute for Public Policy and Social Research at Michigan State University.