Pro-Trump supporters, left, argue with demonstrators after a Feb. 18 march in Los Angeles to protest the president's immigration policies. Sociologists say President Trump's actions and rhetoric are politically energizing both conservatives and liberals. Mark Ralston/AFP/Getty Images hide caption
Protesters attend a rally at Grand Army Plaza in Brooklyn before marching to Sen. Charles Schumer's apartment on Tuesday. Spencer Platt/Getty Images hide caption
Maricopa County Sheriff Joe Arpaio campaigns for Donald Trump in Phoenix in August. Ralph Freso/Getty Images hide caption
Conservative groups have spent more than $1.1 million against Rep. Renee Ellmers, R-N.C., ahead of her GOP primary on Tuesday. Alex Wong/Getty Images hide caption
House Speaker Paul Ryan, R-Wis., responds to a question from the audience during a town hall at Georgetown University last month. Andrew Harnik/AP hide caption
Retiring Rep. Scott Rigell, R-Va. — seen here awaiting election results on Nov. 2, 2010 — says he wants to continue work in his soon-to-be-private life to inject more civility in American politics. Ross Taylor/AP hide caption
Former Alaska Gov. Sarah Palin announces her endorsement of Republican presidential candidate Donald Trump in Ames, Iowa, on Tuesday. Al Drago/CQ Roll Call via Getty Images hide caption
South Carolina Gov. Nikki Haley speaks to the crowd at the Kemp Forum on Saturday in Columbia, S.C. Sean Rayford/AP hide caption
House Speaker John Boehner gets emotional and wipes his face during a news conference on Capitol Hill in which he announced he would be resigning at the end of October. Steve Helber/AP hide caption
House Speaker John Boehner is yet again facing a backlash from conservatives over his approach in trying to avoid a government shutdown. Jacquelyn Martin/AP hide caption
Republican presidential candidates Sen. Ted Cruz of Texas and businessman Donald Trump greet each on stage at a rally on Capitol Hill to oppose the Iran nuclear agreement. Carolyn Kaster/AP hide caption
A woman holds signs depicting the head of Republican presidential candidate and businessman Donald Trump as she waits to enter the auditorium to hear him speak on Wednesday in Derry, N.H. Mary Schwalm/AP hide caption
Rep. Marcy Kaptur, D-Ohio, and fellow Democratic members of Congress hold a news conference to voice their opposition to the Trans-Pacific Partnership trade deal. Chip Somodevilla/Getty Images hide caption