steve handelsman is in detroit with the latest on a race like no other. steve? >> reporter: nothing like it. hi, doreen. here in detroit today some republicans said they will now reassess their support of donald trump. because mitt romney and republicans like him say they should. in the escalating effort by some republicans to beat down donald trump, mitt romney is the heaviest hitter so far. >> donald trump is a phony, a fraud. >> reporter: the 2012 republican presidential nominee welcomed the endorsement of trump then. >> governor romney, go out and get them.

. >> reporter: an this anti-trump push sets the stage for the debate in detroit. a lot of candidates feeling the urgency of the moment. critical time to change this

the chairman of the republican national committee reince priebus is joining us from detroit. thank you very much for joining us. fascinating developments. i've covered politics for a long time. i don't remember when two previous republican presidential nominees, both seem to suggest they couldn't support the current republican presidential front-runner if that front-runner gets the nomination. have you ever seen anything like this before? >> another day, another fascinating development, huh, wolf? have i ever seen anything like this before? not really, but, you know, i haven't been around that long. so i can't really tell you. you know what? nothing surprises me anymore. but the truth is, this process is going to come to a head soon, and we're going to get to a

tonight trump, case you can, rubio and cruz are set to face off in detroit. the debate starts at 6:00 our time and is scheduled to last two hours. it is hosted by fox. you can watch that on the "fox news" channel. >>> the democratic presidential candidates hillary clinton and bernie sanders will debate in flint, michigan on sunday. clinton brought out some star power last night for her campaign. >> ♪[ music playing ]. >> katy perry and elton john performed at a sold out fundraiser at radio city music hall in new york.

amy: hours after mitt romney spoke, donald trump came under more criticism at a debate in detroit hosted by fox news. florida senator marco rubio also focused on trump university, trump's for-profit venture now at the center of a multimillion-dollar fraud claim. >> he is trying to do to the american voter what he did to the people that signed up for this course. he is making promises he is no intention of keeping and it won't just be $32,000 they lose, it is our country that is at stake. the future of the united states and the most important election in a generation and he is trying to con people into giving them their vote just like he conned these people into giving them their money. >> excuse me, excuse me. the real con artist is senator marco rubio. who was elected in florida and

and we may see more of that tough talk in a little less than an hour from now in detroit. that's when donald trump will take the stage for the latest republican debate. texas senator ted cruz, florida senator marco rubio and ohio governor john kasich are also taking part. watch on the fox news channel. >> horrifying accusations against a nanny in the east bay. police say mariah gonzalez was caught allegedly using her hands to smother a crying 13- month-old boy.

. >> reporter: for "good morning america,jim avila, abc news, detroit.

. >>> the republican debate in detroit, michigan, did not disappoint, that is, if you were looking for a slug fest. rubio and cruz all said they would support trump if he's the nom yoe. rubio, trump and cruz did not >> he's trying to con people to giving them his vote. >> the real con artist is rubio who was elected in florida and has the worst voting record in the united states senate. he's absent. the people of florida can't stand him. he couldn't get elected dog catcher. >> this little guy lied so much about my record. >> here we go. >> he has lied so much about my record. >> senator rubio, let him talk. >> well it got ugly. look at how last night's results and week's events will impact here in florida. i'm joined by vice chair. thank you so much for joining us. >> thanks for having me. >> so much has changed since we last spoke. last night's primary results, rubio didn't do so well last night and his campaign is saying is because cruz does better at organizing in caucus states but what was your take on last night? >> not only do we find that to be true that caucuses seem to lean in