p.j. crowley, who served as assistant secretary of state during the first obama administration and is nowellow at george washington university. mark, i want to start with you. from your sources in the intelligence community, is there any certainty on whether the surface to air missile was from russia or from the rememberrals. >> not certainty on that point. you heard president obama put the point pretty clearly on moscow today either they did it themselves or they give it to the rebels and doing this by proxy. either way the president said intelligence officials are sort of pointing out, it's russia is escalating the conflict by introducing these surface to air missiles. but you raise a good point, exactly how this happened, exactly how the missiles got there and when they got there is still an important point and question to answer. >> sreenivasan: is there any kind on time line how they could make such a determination. >> it would be going back to satellite images looking at the plumes of smoke, about where exactly these were fired, going back to intelligence. we heard in the last coupl

p.j. crowley and michael weiss join me. p.j., start with you. no one now seems to suspect that vladimir putin said let's take out a commercial jetliner. certainly as we said the suspicion here is strong about, you know, a russian weapon, pro russian are area of ukraine where it happened. potentially, as susan power suggested, training are from russians for this to happen. let's say that's what is proven. say the united states investigators are able to prove that. what happens then? >> it's still an open question. there is no question that russia's policy is to destabilize eastern ukraine to gain leverage over the new ukraine government. how close russian fingerprints get to to the shoot-down will be important in terms of how significant the reaction is, particularly how significant in euro europe. there is a disadvantage to the relationship. ukraine is more important to russia than to the united states. to the extent that the challenge is to impose costs on russia for the foreign policy, for actions to work with the separatists and destabilize u

p.j. crowley forme. how likely do you think a ground invasion of gaza is at this point. >> there is pushing on both sides to continue this conflict at least for the time being. along with this goes on the greater likelihood of escalation on one or both sides. >> the sooner one can achieve a cease-fire the better. one will come. we've gone through this cycle of violence before. you know, 2008-2009, you know, 2012. but as nick schifrin's reporting suggest that for the moment both sides seem to be intent on trying to inflict as much damage or terror on the other. to have the dialogue and try to find a way to at least first prevent further escalation, and second, find a way to achieve a cease-fire. >> i do want to ask you about the potential for cease-fire. but you brought up a good point. both sides here are trying to inflict as much damage on the other. but as we've shown our viewers throughout this week and some video just now and earlier reporting, it's a very lopsided affair in terms of what israel coul

p.j. crowley is a former assistant secretary of state, and an al jazeera board member. j., welcome. >> hello, john. a planned offensive like this had to have been planned stuff obviously it is cliff kateed and takes time. so has israel been planning this for a while inform well, israel had a great does he feel of experience, obviously we also saw a version of this in 2012. the rockets have periodically hit israel over several years and they have been closely tracking hamas as a military threat. and obviously been prepared to respond both in the air and now on the ground. >> and how will hamas respond, do you think. >> well, you have the two agendas here. israel quantities to try to impose as much damage on hamas' capability as possible, for as long as they can operate securely in that area. hamas is coming at this from a relatively weak stand point, weaker than they were in 2012. and 2008. for example, they lost their home, when they backed the syrian opposition. they lost one of their leading advocates when egyptian president mohammed morrissey was turned out of power.

p.j. crowley. the diplomatic untangling. we are talking about the potential of russian-made missiles that came perhaps to these rebels, these separatists from russian territory. there are multiple nationalities on these aircrafts. you'll have americans and nationalities from many other citizens including perhaps china. so there are going to be a lot of countries angry about what happened here. a lot of countries that will be looking for explanations as the news develops. so we can look at it from the frame of the u.s. and russian relations and no question there is significant tension for that right now and this goes back to kind of and there will be many countries with the russian support for the separatists and the deadly game that russia has been playing should the evidence point in that direction. by the same token, i wouldn't necessarily expect an immediate mea culpa, you know, from russia. if i remember correctly, russia hasn't even acknowledged that syria used chemical weapons last year. so we may well have an idea qui