Michael was there to kill Sollozzo, there was no guarantee McCluskey would even be at the table...if he got "the turk" sollozzo could have been ignored, would have saved a lot of grief - but the good Captain had to ask how the Italiian food was...he should have stepped next door for a bowl of Irish stew

I also think it 100% certain Sollozzo was armed, while McCluskey may have not been, or at best may have had a back up weapon - I mean, nobody would ever dare kill a New York Police captain....

Sollozzo was known to even be deadly with a knife, no small claim in a modern world