It's not the easiest of questions to answer but I'd say it's pretty unlikely that they ever would be attacked again, they have strong ties in the EU now and I don't think that Russia is too interested in them.
If history teaches us anything then I don't think Poles should feel safe because they are a part of EU or any other pact. The goods usually go to the highest bidder and in this case it is Russia. They have gas and oil that EU wants, and at least for the next 50 or so years Russia does hold some trump cards.
The German-Russian Baltic pipeline deal just goes to show how really EU countries stick together. Shroeder didn't think twice about agreeing to the Russian demand of bypassing Poland, even though technically and financially the pipeline would make much more sense if it ran on land. How long did it take before EU took a strong stance on Polish meat exports to Russia? That should have been an automatic and overnight decision.
This also goes to show how "little" Russians are interested in Poland. They are still pis.sed off that they lost it and this is not the end of it, I'm afraid.
As for handling another war, the history of Poland as a state is a tad longer than that of Britain, and unlike British wars, most of those fought by Poland were on their own territory. It's a 1000 year long history of attacks by practically all neighbors, and them some others. The nation survived and I think it will.