Sen. Richard Shelby of Alabama - Democrat to Republican: Richard Shelby, the senior senator from Alabama, switched parties on Nov. 9, 1994, one day after the ‘Republican Revolution’ in which the GOP became the majority in the 104th Congress. Shelby’s switch gave Republicans 52 Senate seats. Here, Shelby talks to reporters on Capitol Hill in Washington on April 28. Charles Dharapak/AP
Gov. Sonny Perdue of Georgia - Democrat to Republican: Sonny Perdue, currently Georgia’s governor, was a state senator when he switched from Democrat to Republican in 1998. He was reelected that year and again in 2000. He ran for governor as a Republican and was elected in 2002. Perdue said he switched when he gained clarity after his father’s death in 1998 and because of differences with a national party more liberal than he. Here, Perdue greets members of the 48th Brigade as they arrive at Hunter Army Airfield from a year-long deployment to Afghanistan on April 7 in Savannah, Ga. John Carrington/The Savannah Morning News/AP
Sen. Jim Jeffords of Vermont - Republican to Independent: Jim Jeffords, a senator from Vermont, was a Republican until May 2001. A liberal/moderate Republican, Jeffords said he increasingly found himself “in disagreement with my party.” His switch gave Democrats control of the Senate; in return, he got a key committee chairmanship where he could champion issues important to him. Jeffords retired from the Senate in 2007. Jeffords is seen here shaking hands at a party for the retiring politician in August 2006 in Shrewsbury, Vt. The Daily Herald/AP/FILE
Mayor Michael Bloomberg, New York City - Democrat to Republican to 'Unaffiliated': Michael Bloomberg, a longtime Democrat, became a Republican to run for mayor of New York City in 2001. Bloomberg rode the coattails of popular GOP Mayor Rudolph Giuliani into office, but eventually left the Republican Party. He said he felt that a nonpartisan approach worked, though many see the switch as sign he’ll seek national office. Here, Bloomberg enters a news conference to talk about the benefits of the Opportunity NYC-Family Rewards Program in The Bronx in New York City on March 30. Robert Mecea/AP
Sen. Joe Lieberman of Connecticut - Democrat to Independent: Joe Lieberman, the junior senator in Connecticut, holds positions that do not conform to one party. After losing the Democratic primary to newcomer Ned Lamont in 2006, he opted to run as an Independent. His campaigning for Republican presidential candidate John McCain in 2008 put him at sharp odds with Democrats, as did his rejection of the Medicare buy-in plan during the health-care debate. He caucuses with the Democrats. Lieberman is acknowledged here at a banquet of the American Israel Public Affairs Committee (AIPAC) annual policy conference in Washington on March 22. Jonathan Ernst/Reuters
Sen. Jim Webb of Virginia - Republican to Democrat: Jim Webb was Secretary of the Navy under President Ronald Reagan. In February 2006 he announced he would seek the Democratic nomination for Senate in Virginia. Victorious in the Democratic primary against Harris Miller, he narrowly defeated incumbent Sen. George Allen (R) on Nov. 9, 2006. In an NPR interview, Webb said he had supported Republicans on foreign policy but had never been comfortable with the party platform on economic and social issues. Here, Webb gestures during a news conference on Capitol Hill on March 9 in support of the National Criminal Justice Commission Act. Manuel Balce Ceneta/AP
Rep. Parker Griffith of Alabama - Democrat to Republican: Parker Griffith, representing Alabama’s Fifth Congressional District, clashed frequently with fellow Democrats, voted against an anti-global-warming bill, and was a critic of health-care reform. Griffith is seen here discussing his decision to switch parties in Huntsville, Ala. He cited the Democrats’ fiscal policy as one reason for leaving the party, a year after being elected in 2008. Jay Reeves/AP/FILE
Sen. Arlen Specter of Pennsylvania - Republican to Democrat: Arlen Specter said that the Republican Party had moved too far to the right and that he was “increasingly at odds with the Republican philosophy and more in line with the philosophy of the Democratic Party." Specter’s switch helped Democrats obtain the coveted 60-seat, filibuster-proof majority (for about nine months). Specter is seen here speaking at a gathering sponsored by labor unions and citizen activist groups in Harrisburg, Pa., on Jan. 30. Carolyn Kaster/AP/FILE
Gov. Charlie Crist of Florida - Republican to Independent: Charlie Crist has become unpopular with Republicans in Florida, as well as in Washington, D.C. He angered many when he endorsed Obama’s economic stimulus law. Now running for Senate, he faced a stiff primary challenge from Marco Rubio, a ‘tea party’ movement favorite. Becoming an Independent makes it possible for Crist to stay in the Senate race until the general election. Stephen J. Coddington/St. Petersburg Times/AP
Sen. Ben Nighthorse Campbell of Colorado - Democrat to Republican: Ben Nighthorse Campbell considered himself a moderate among his peers. He moved to the Republican Party after the Senate defeated the balanced-budget constitutional amendment, which he favored but which most Democrats did not. Campbell kisses a bison named Harvey during a press conference in front of the Russell Senate Office Building in Washington on Capitol Hill in July 2004. Valerie Roche/Scripps Howard News Service/Newscom/FILE
On Saturday, German Chancellor Angela Merkel made her first trip to Ukraine since fighting broke out four months ago between pro-Russian separatists and government forces. Merkel pledged her support for a path toward peace.
ByNatalia Zinets and Richard Balmforth, Reuters
German Chancellor Angela Merkel flew in to the Ukrainian capital on Saturday and said she wanted to help end a crisis over Ukraine which flared again after Russia sent a convoy of trucks into Ukraine without Kiev's permission.