Q: How might US citizenship affect my Dutch and Canadian dual citizenship?

A: Your Dutch and Canadian citizenships should remain secure when acquiring US citizenship through your spouse. The key factors supporting this are:

The Dutch government specifically allows dual citizenship when you acquire a foreign nationality through marriage. This is one of three exceptions to their general rule about losing Dutch citizenship when acquiring another nationality. Your situation fits precisely within this exception, which is why your friend who didn't acquire US citizenship through marriage had a different outcome.

While the US Oath of Allegiance does contain strong language about renouncing "all allegiance and fidelity to any foreign prince, potentate, state, or sovereignty," in practice, this doesn't require you to formally surrender your other citizenships. The current US State Department policy provides that you don't need to choose between citizenship in the US and your home countries, and US courts have upheld this approach.

From the US perspective, the oath is largely ceremonial rather than legally binding in terms of forcing you to actually surrender foreign citizenships. The State Department explicitly states that "US law does not mention dual nationality or require a person to choose one nationality or another."

You'll need to be mindful of your responsibilities to all three countries, including using appropriate passports when entering or leaving each country, and following their respective laws. Each country will view you primarily as their citizen when you're within their borders.

To fully protect your Dutch citizenship, ensure you're following their specific procedures for maintaining dual citizenship in your case. Consider contacting the Dutch embassy for confirmation that your circumstances qualify for the marriage exception, as immigration laws can have nuances that require official clarification.