FACTBOX: Leading presidential candidates on immigration

(Reuters) - With just two weeks before Iowa begins state-by-state battles to choose the Republican and Democratic candidates for the U.S. presidential election in November 2008, politicians are walking a careful line between appeasing anti-immigration sentiment and trying not to turn off a growing segment of Hispanic voters.

Following is a summary of the leading presidential candidates' positions on immigration reform.

DEMOCRATS:

New York Sen. Hillary Clinton

Supports a guest-worker program for immigrants if it does not undermine U.S. workers' wages and favors giving undocumented workers a way to become legal workers. Supported the building of a border wall. Urges development of an employer verification system and higher penalties for employers who exploit illegal immigrants.

Former North Carolina Sen. John Edwards

Urges doubling the number of Border Patrol agents, installing surveillance technology to police the border and increasing enforcement against employers who hire illegal immigrants. Supports allowing illegal immigrants to become U.S. citizens if they avoid a criminal record, pay a fine and learn English. Opposes a guest-worker program that does not include workplace safeguards.

Illinois Sen. Barack Obama

Backs additional personnel, infrastructure and technology to safeguard U.S. borders and ports. Urges reducing application fees and improving speed and accuracy of FBI background checks for immigrants. Supports a program in which illegal immigrants pay fines, learn English, do not violate the law and go to the end of the line to become citizens. Favors creating a program for employers to verify an applicant's immigration status.