Christie and Fiornia have dropped out. We can count Gilmore out as well (since nobody even knows who he is). That leaves 6 technically in the race: Trump, Cruz, Rubio, Bush, Kasich, and Carson.
However, the race for the nomination includes both winning elections, and having enough money to win future elections. If we review January’s numbers we will see that Carson and Kasich cannot continue. Carson spent $5M more in the fourth quarter than he brought in, and ended the quarter with $6.6M in the bank. In January and February his support was half of what it was in 4Q meaning we would expect his donations to go down. Also he had to actually run in elections meaning his spending went up. He is out of money, and out of support.
Kasich brought in little and spent little and ended last year with $2.5M. He won New Hampshire which should be a means for him to build out donations, but those donations probably won’t start until he can demonstrate he is more than a New Hampshire wonder boy. That is, funds won’t turn on until he performs well in another state, and in Kasich’s view that is scheduled for March 6th. Not gonna happen. He is out of money, has never had national support, and will be out before NV.
That leaves 4, Trump, Cruz, Rubio, and Bush. Bush is banking on riding another slim victory over Rubio in SC. He has a chance at that, which is why he is not out. I don’t think its going to happen, but there is still a viable path forward for Bush (he takes out Rubio in SC, places second in the SEC primary, wins Michigan, and does well thereafter).
I think it is likely that the 7 points nationally that switched suddenly from Trump to Rubio is up for grabs after New Hampshire. If Carson were to drop out and Cruz picked up Carson’s support and the 7 points then Cruz would lead Trump nationally. If Kasich were to suspend his campaign during the next debate and make a passionate appeal for Rubio then Rubio would best Cruz in SC and go on to beat Trump nationally. If both Carson and Rubio cling on for dear life they can hand SC and NV to Trump, leave Rubio and Cruz well below Trump and allow a three way race into a Trump victory or brokered convention. Several possibilities, but there are now only 4 candidates and 2 spoilers.