Legalisation of undocumented: Senate allows most illegal immigrants to remain in the US and eventually apply for citizenship. House of Representatives allows for no such provision.
Temporary worker programme: Senate allows up to 200,000 people to enter US each year as temporary workers with the possibility of permanent legal residence. House allows for no such provisions and abolishes Diversity Visa Lottery.
Penalties for illegal immigrants: Senate proposes criminal penalties for those who smuggle in aliens, but makes an exception for those who offer humanitarian assistance, including medical treatment. The House proposes that it would be a federal crime to live in the US illegally and that those who help illegals would face criminal penalties.
Worksite enforcement: Senate says employers must screen all new employees for legal status or face a $200,000 fine, and must join an electronic verification system within 18 months. The House says employers must join an electronic verification system within six years.
Border security: Senate allows for 563km (350 miles) of border fencing and 805km (500 miles) of vehicle barriers between the US and Mexico, plus 2,400 new border guards each year until 2011. The House allows for 1,127km (700 miles) of reinforced fencing, physical barriers, roads, lighting, cameras and sensors along the border with Mexico.
