The fight for the 2016 GOP nomination appears to be moving into a new, more fluid phase.
No longer is the question merely whether or how Donald Trump can be stopped.
23:34 Trump joins the effort to pass a health-care bill, but another GOP senator is opposed12
10:47 With a raucous rally in Cedar Rapids, Trump transports himself back to 201621
02:31 In Iowa, Trump rallies base, celebrates GOP resilience26
02:19 Back in campaign mode, Trump hits on immigration and a border wall31