U.S. Republican presidential candidate Donald Trump listens as his daughter Ivanka speaks at a campaign rally on caucus day in Waterloo, Iowa, Feb. 1, 2016. REUTERS/Rick Wilking

With the Iowa caucuses Monday, the Republican candidates are covering every inch of the early-voting state to make their last pitches to voters. While Donald Trump is leading in polls, the remaining 11 candidates are battling for those final undecided votes before a winner is announced Monday night or sometime Tuesday. Here’s a guide to the GOP field and what they say they will do if they make it to the White House, using data collected by the nonpartisan politics website On the Issues.

Donald Trump: The business mogul from New York, who has never held office, has led the Republican polls for months, relying on his brash personality to claim much of the limelight from his rivals. In addition to building a wall on the Mexican border, and getting the Mexicans to pay for it, the "Apprentice" reality star wants to stop gun tragedies by expanding treatment facilities for people with mental health problems. He also promised in October to defund Planned Parenthood.

Donald Trump poses while giving a speech in South Carolina in 2015.
GOP front-runner Donald Trump wants to build a wall at the Mexican border and expand mental health facilities. REUTERS/Randall Hill

Jeb Bush: The governor of Florida from 1999 to 2007 is well known as a moderate on immigration and a staunch critic of Obamacare. If elected president, the son of former President George H.W. Bush would reform the tax system to just three brackets instead of seven and have a top tax rate of 28 percent. He would also offer more support for the Kurds in Iraq to help them defeat the Islamic State group.

Ben Carson: The retired neurosurgeon, who has never held office, wants to include a balanced budget amendment to the Constitution, keep Guantanamo Bay open and nix federal funding to Planned Parenthood.

RCP Poll Average Week-Over-Week for GOP Presidential Candidates | InsideGov

Chris Christie: The moderate conservative and current governor of New Jersey is a proponent of drug rehabilitation in his state and across the country, has promised to undo defense sequestration and says he will build a wall in certain areas of the U.S. border with Mexico.

Ted Cruz: The conservative Canadian-born senator from Texas once read Dr. Seuss' "Green Eggs and Ham" during a filibuster to try to defund Obamacare, which he said he would attempt to repeal if elected president. As well as opposing the Export-Import Bank, the Harvard Law graduate wants states to be able to have their own definition of marriage.

Carly Fiorina: As the only Republican woman in the race and the former CEO of Hewlett Packard, Fiorina has spoken a lot about the glass ceiling for women and said Democratic front-runner Hillary Clinton would be bad for women in America. The onetime candidate for a U.S. Senate seat from California, Fiorina supports the Dream Act, which would allow qualified undocumented immigrants to earn legal residency. She also wants to arm Ukraine to fight Russian-backed rebels in the eastern Ukraine war and cut federal tax revenues.

Jim Gilmore: Former governor of Virginia Gilmore was a late comer to the debates Thursday after making his first appearance in the undercard group. The U.S. Army veteran wants to repeal Obamacare and deport all illegal immigrants. He believes in climate change, but doesn’t think Obama’s cap-and-trade solution, which sets a limit on emissions and opens a market for carbon allowances, will work.

Mike Huckabee: As a GOP presidential candidate from 2008, Huckabee, a former Arkansas governor, has been through the process before. He wants to eliminate income tax and replace it with a federal sales tax, also known as a FairTax. As well as supporting a unified Jerusalem, he is an ordained Southern Baptist minister and says he would abolish the Department of Education.

John Kasich: The current Ohio governor served in Congress from 1983 until 2001 as a representative from the state’s 12th district. He wants to lift defense spending caps and allow health insurance programs to be run by the individual states. He also supports shutting down Planned Parenthood.

Rand Paul:

The Kentucky senator and son of former presidential candidate Ron Paul wants to simplify personal income tax to one rate of 14.5 percent and wants to audit the Federal Reserve while also shifting its regulatory powers back to Congress.

Marco Rubio: The son of Cuban immigrants to the U.S., Rubio was part of the “Gang of Eight” that proposed a plan to citizenship for undocumented immigrants living in the U.S. He has been a Florida senator since 2011 and if he became president would split the tax code into two brackets, 15 percent and 35 percent, and would scrap Obamacare.

Rick Santorum: During his 2012 presidential campaign, Santorum had some success, notably finishing second in GOP primaries and winning the Iowa caucuses. But so far in 2016 he has not recorded good polling numbers and has largely been on the fringes of the debate. If he does make it to the Oval Office, the former U.S. senator from Pennsylvania wants to reduce legal immigration by 25 percent and slim down the IRS.