Texas and Ohio hold Democratic primaries Tuesday that are seen by many as must-win for Hillary Rodham Clinton. She'll be in both states today while rival Barack Obama focuses on Texas.
Bill Clinton stumps for his wife at Bryant University in Rhode Island today.
Obama has won 11 state contests in a row and Clinton backers say she needs strong showings Tuesday to resuscitate her campaign.
Adding to Clinton's problems, she's lost the support of a key superdelegate to next summer's convention. Georgia Congressman John Lewis has switched his endorsement to Obama, saying his campaign is becoming "a new movement in American political history."