As for Democrats, they’ve been slightly more successful in holding onto their share of the electorate:
Democrats’ advantage in leaned party affiliation appears to be expanding, as it was six points (46% to 40%) in the fourth quarter of 2017 compared with four points in both the second and third quarters. Gallup found similar Democratic gains late in the year in an analysis of monthly data from its daily tracking survey.
Nevertheless, they too will need to go after independent voters if they are to retake the House and/or Senate. Greater political independence “could also explain the more frequent changes in party control of Congress, with the majority party in the House of Representatives switching three times since 1994 — after the 1994, 2006 and 2010 midterm elections — after 40 consecutive years of Democratic House majorities,” Gallup finds. “Americans will vote in midterm elections this fall to elect a new Congress — and with an unpopular incumbent president, the increase in independents may only escalate the chances that party control of Congress will change hands once again.”
A word of caution is warranted. The presence of so many independent voters does not mean these are necessarily moderates. Most every poll shows the once-great center shrinking and more polarization at the extremes. If Democrats want to capitalize on the GOP woes and the general unpopularity of the president, they might want to consider running on his failure to carry through on populist economic reforms, his attacks on the health-care system, his self-deal and conflicts of interest and the Republicans utter failure to act as a restraint on the unhinged chief executive.