PrimeTime Politics U.S. President Barack Obama speaks at a memorial service in Tucson, Arizona for the victims of Saturday’s mass shooting.Opposition leader Michael Ignatieff returns from his holiday with an event on Parliament Hill to kick off his “20/11” tour: 20 non-Liberal ridings in 11 days. Ignatieff answered questions on the tour and Canada’s dispute with the United Arab Emirates over military bases and commercial flights. Finance Minister Jim Flaherty speaks in Washington, D.C.