The best illustration of this plan came in South Carolina, where Rubio had a strong performance in a debate just days ahead of the primary, held several well-received rallies and, finally, won the endorsement of the popular governor, Nikki Haley (R).
They can fulfill their pledge by voting against Pelosi in the "primary" held in the Democratic caucus.
She received 13,477 votes (38.3 percent) in the primary held on October 22 and promptly withdrew from the November 19 general election.
The primary hold-up, to this point, has been his past statements on the KKK and his positions on the civil rights movement.
In the primaries held since the beginning of March, the increase has been more than 50percentt.
The Democratic National Committee refused in advance to acknowledge the primaries held in Florida and Michigan because they were scheduled earlier than permitted under party rules.
In terms of raw votes, Clinton has won 10.1m ballots in the primaries held so far and Trump has obtained 8.5m.
Current popularity is no guarantee of future success as Mr Prodi, who won an overwhelming majority in the primaries held by the Unione coalition in October 2005, can attest.
