The presidential race is revolving around key contests in two delegate-rich states: Texas and Ohio.
The candidates criss-crossed the Lone Star State on Friday.
Next Tuesday's primaries are predicted to be close between Barack Obama and Hillary Clinton.
Clinton has launched an aggressive ad campaign to try and show voters she's the best equipped candidate to protect American families from day one.
Meanwhile, Obama continues to clash with Republican John McCain over the war in Iraq.
McCain says Obama is focusing on how the war started, not how America can win.
"That's history. That's the past. That's talking about what happened before," McCain insisted. "What we should be talking about is what we're going to do now."
Obama said, "I may honor his service - but his policies are wrong."
The results next Tuesday in Texas could hinge on the Hispanic vote.