Candidates battle for 20 La. delegates

>>> open right now. it is the latest primary battleground for the gop nomination. 20 of the bayou state's 46 delegates are at stake. mitt romney has an easy lead in the current delegate count. join me as nbc news senior political editor mark murray . so when do you think mitt romney can get the 1144 delegates needed to secure the race.

>> if mitt romney ends up winning all the delegates that are in stake at all of the different contests, he really won't cross that imagine gal number of 1144 delegates until may 29th . that's the texas primary . so essentially, two months from now. if you actually say that mitt romney is going to win a 60/40 split of all of the delegates, he won't cross that 1144 mark until june 26th . but if you think they're going to trade contests like we've seen them do over the past month and a half, there is, according to our math, that mitt romney isn't going to reach that 1144 mark. that's our challenge. he has the delegate lead. but when he actually wraps up that magical number, it won't be for quite a while. he might not even do it after the last primary on june 26th .

>> it looks like newt gingrich was crunching the math just like you were. you heard him say mitt romney may not get to the convention.

>> well, right. and so that's -- that's the challenge for newt gingrich . actually the challenge for rick santorum . they might say this may not be wrapped up until the convention, but mitt romney has a very substantial lead right now. this comes down to math versus perception. and rick santorum is the favorite tonight. the perception is going to be mitt romney is a front runner , even though he may not reach the 1144 number for quite a while. those are the two themes going on, perception versus math.

>> what has been the fall out with rick santorum talking about instead of voting for him, maybe you should just stick with what he had in president obama ?

>> he got quite a bit of blow back from that comment. that all came in context with he described mitt romney as an etch-a-sketch republican. they say, look, anyone would be better than president obama , any republican would be. so that's the reason he walked it back.

>> thanks so much. that is