I would say at this point in time America's most likely conflict will be with North Korea. North Korea seems to be pretty unstable and the Korean War was never officially ended, only a cease-fire has staved it off this long. I have my doubts America will enter Yemen or get involved.
Get the name of the country right, please. It's the United States. And no, our next war will not be in Yemen. The political situation there is toxic, but the last thing that government wants is to be used as a proxy battleground for the new Cold Warriors of the 21st century. It will more than likely be in Iran or China.
No, I do not think that America's next war will be in Yemen, because there are other countries that are doing more to harbor terrorists than Yemen. There are a lot of terrorists in Pakistan, even though they claim to be our friend. Palestine is perilous, and there are people in Iran that wish to hurt us as well.
While Yemen is a hotbed for terrorism, I don't think the United States will be invading Yemen any time soon. This is mainly because the American people are very tired of war, and tired of conflicts in the Middle East. Also, the best way to combat terrorism is through intelligence, not a land war.
I think the American public and American Government itself is very war weary after the long wars in Afghanistan and Iraq, I think the next war that America will involve itself in will likely be in Syria or perhaps having to go back into Iraq, I don't think the American Government is planning to attack Yemen.