can you marry someone to get them legally into the US?

With the way current BCIS/INS procedures are, there's a good chance the agent assigned to your case won't see the parties involved within the year, so - yes - there's a chance this will remain undetected.

However, there are some things to be considered. First, it is a crime to enter the United States with the intend to get married and receive a visa. While it's not a crime to come to the US, fall hopelessly in love, and get married, crossing the border to get married is verboten. If the agent feels this was the case an extradition will be likely. Secondly, if the agent concludes that this marriage is not in "good faith", that is wasn't done out of love but, for example, to get someone a residency, the same procedures apply - and the American entering into the marriage is liable to be charged, as well.

Now, mind you, arranged marriages and other such nonsense are considered "good faith", so it's once again up to the agent to decide.

All in all, it's a dangerous enterprise you are about to undertake. Be prepared for the agent to ask questions as to your love life, the number and times you made love, which side your spouse sleeps on in your bed, snoring, favorite tooth paste and - if the agent deems it necessary - for BCIS investigators to be at your doorstep at odd hours to discern wether you are, indeed, living with this person and have an intimate, spousal, relationship.

That all said, I am one of those people who genuinely fell in love in the US and got married. We weathered the inquisitive work, we stood in line at the INS (now BCIS) more than I ever stood in line anywhere, I spent nights (arrive at 11pm to be far enough in line to get in at 9am the next morning due to INS "maximum visitors per day" regulations) and days at the local BCIS office, and still did some hefty paperworking and following up over the course of three years until I was deemed a legal entry.

Lastly, a warning. While BCIS investigations are ongoing, your spouse will not be able to leave and re-enter the country easily. Without a complicated petition process called an "advance parole" she'll be stuck in the US, come hell, high water, or family issues in Africa, for at least 2 to three years at the current pace.

NO,

getting married for the purpose of getting entrance to the US is illegal.
This couple was arrested for this.

http://cbs2.com/local/craigslist.greencard.marriage.2.605806.html

Hello..I hope you can help us///I am a 56 year old disabled man living in Mass and my fiance is in Ghana South Africa. we wish to marry and I really need her help. We are hopelessly in love and wish to marry and have a child before we get to old neither of have any children and we wish to have a child..I will crawl thru fire for her..what do I have to proceed// Thank you so very much for your help

What steps do i need to take to legally marry someone from Ghana? If she has a regular visa and passport,how long can she legally stay? can she convert her regular visa to a fiance visa or a work visa,after entering the US? When does INS get involved? I want to do everything right and legally.