Depends what you mean by tough, the United States requires that you take a US history class and pass a test. One of the hardest countries to get into is Australia, you MUST have a college degree that the government wants, you need to have a certain net worth (no poor people), a clean criminal record, and there is also a 4-6 year waiting period.

The extremely strict immigration laws of Denmark have dramatically reduced the flow of people into Denmark. M Fewer immigrants means less money going into welfare and a lot of government figures are delighted with this outcome. I wonder if Washington should send people to Copenhagen and see how they do it and takes copious notes.

Every country has its own strict set of rules that govern the entry of immigrants to their country. It is essential that these laws are made strict for the purpose of the country's security. Russia, US have very strict laws as these are countries that are the most targeted ones by terrorists and other miscreants.

Ironically some of the nations that send out the most immigrants are the toughest to get into.Mexico is an example.An illegal immigrant may get upto 2 decades in prison.Obtaining citizenship in Russia,much of Africa and Asia is hard and in the case of Japan and South Korea,next to the immposible unless through marriage.Unlike the US,Birthright citizenship does not exist in these countries.You cannot become a citizen in middle eastern nations like KSA or Qatar even if you live there your whole life unless under special circumstances(like the athletes poached from Kenya by Qatar.).Nations like Australia,New Zealand,South Africa and Singapore provide permanent residency and citizenship based on skills and investments only.

Saudi Arabia. You cant get a tourist visa, an unacompanied woman cant enter the country, (unless she is sponsored for employement) No Isrealis allowed, and no one with an israeli stamp on thier passport allowed. Work visas and visas for business meetings are granted, provided the employer is well recognised by the government. Muslims can get visas to make a pilgrimage to mecca. Transit visas for flyers are granted, but not to single unacompanied women, transit visas are also granted to truckers driving across the country. No non muslims are ever given permanent residence, and no forigners of any description are ever given citizenship.

King Abdula said, "his kingdom will only survive, as long as the forigner finds that with his task complete, he will have no other aim but to get out.