Can a us citizen parent living in a foregn country return to the us with the kids without the other parents consent?

First ANY question on law needs to include your general locale as laws vary by area. Second, are you planning on divorcing? Is a divorce in progress? Has any court action been decided? Are the children citizens of that country? Do they have passports and if so, from what country?

In some countries, like the US, parental consent is required by both parents to exit a country, unless the single parent has proof of sole legal custody.

But we need a lot more background for us to be able to help.