Scenarios in US political race

Democrat Hillary Clinton's victories in Tuesday's US presidential voting in Ohio and Texas have stopped the momentum of rival Barack Obama and put her back in the race for the party's nomination.

Republican candidate John McCain won four contests on Tuesday and clinched his party's presidential nomination for the November election. Here are some scenarios for the presidential nomination battle.

Democrats

The next two battlegrounds are Wyoming on Saturday and Mississippi next Tuesday.

Mr Obama appears strong in both states but the real contest that awaits the two candidates comes on April 22 in Pennsylvania.

That state has demographics similar in many ways to Ohio, which provided Mrs Clinton a clear win on Tuesday.

After Pennsylvania, eight more contests are scheduled in May and June. Even after losing on Tuesday, Mr Obama still held the lead in pledged delegates to the August national convention that will pick the next nominee. Mrs Clinton will have a tough time cutting into Obama's lead and may have to rely on the "super delegates" who can vote for anyone they want.

Republicans

With no serious Republican to challenge him, Mr McCain can begin a national campaign and try to set the agenda for an autumn race against either Mr Obama or Mrs Clinton.