A look at where Democrat Barack Obama and Republican John McCain stand on a selection of issues:
McCain: Opposes abortion rights. Has voted for abortion restrictions permissible under Roe v. Wade, and now says he would seek to overturn that guarantee of abortion rights. Would not seek constitutional amendment to ban abortion.
Obama: Favors abortion rights.
McCain: Favors unspecified boost in U.S. forces.
Obama: Would add about 7,000 troops to the U.S. force of 36,000, bringing the reinforcements from Iraq. Has threatened unilateral attack on high-value terrorist targets in Pakistan as they become exposed, "if Pakistan cannot or will not act" against them.
McCain: The co-author of McCain-Feingold campaign finance law, he plans to run his general campaign with public money and within its spending limits. He has urged Obama to do the same. He applied for federal matching funds for primaries but later turned them down so he could spend more than the limits. Federal Election Commission belatedly approved his decision to bypass the primary funds, but rejected McCain's claim that he needed no such approval. McCain accepts campaign contributions from lobbyists.
Obama: The presidential campaign's fundraising champion has brought in $390 million. He plans to raise private money for his general election, despite his proposal last year to accept public financing and its spending limits if the Republican nominee does, too. Obama refuses to accept money from federal lobbyists and has instructed the Democratic National Committee to do the same for its joint victory fund, an account that would benefit the nominee. Obama does accept money from state lobbyists and from family members of federal lobbyists.
McCain: Ease restrictions on Cuba once U.S. is "confident that the transition to a free and open democracy is being made."
Obama: Ease restrictions on family-related travel and on money Cuban-Americans want to send to their families in Cuba. Open to meeting new Cuban leader Raul Castro without preconditions. Ease trade embargo if Havana "begins opening Cuba to meaningful democratic change."
McCain: Has supported expansion of the federal death penalty and limits on appeals.
Obama: Supports death penalty for crimes for which the "community is justified in expressing the full measure of its outrage." As Illinois lawmaker, wrote bill mandating videotaping of interrogations and confessions in capital cases and sought other changes in system that had produced wrongful convictions.
McCain: Favors parental choice of schools, including vouchers for private schools when approved by local officials, and right of parents to choose home schooling. More money for community college education.
Obama: An $18 billion plan that would encourage, but not mandate, universal pre-kindergarten. Teacher pay raises tied to, although not based solely on, test scores. An overhaul of President Bush's No Child Left Behind law to better measure student progress, make room for non-core subjects like music and art and be less punitive toward failing schools. A tax credit to pay up to $4,000 of college costs for students who perform 100 hours of community service a year. Obama would pay for his plan by ending corporate tax deducations for CEO pay and delaying NASA's moon and Mars missions.
McCain: Favors increased offshore drilling and federal money to help build 45 nuclear power reactors by 2030. Opposes drilling in Arctic National Wildlife Refuge. Proposed suspending the 18-cent a gallon federal gasoline tax but idea got no traction. Global warming plan would increase energy costs.
Obama: Now would consider limited increase in offshore drilling. Opposes drilling in Arctic reserve. Proposes windfall-profits tax on largest oil companies to pay for energy rebate of up to $1,000. Opposed suspension of the gas tax. Open to tapping the Strategic Petroleum Reserve for short-term relief from high energy costs. Global warming plan would increase energy costs.
McCain: Opposes constitutional amendment to ban it. Says same-sex couples should be allowed to enter into legal agreements for insurance and similar benefits, and states should decide about marriage. Supports the federal Defense of Marriage Act, which denies federal recognition of same-sex marriages and gives states the right to refuse to recognize such marriages.
Obama: Opposes constitutional amendment to ban it. Supports civil unions, says states should decide about marriage. Switched positions in 2004 and now supports repeal of Defense of Marriage Act, which denies federal recognition of same-sex marriages and gives states the right to refuse to recognize such marriages.
McCain: Broke with President Bush on global warming. Led Senate effort to cap greenhouse gas emissions; favors tougher fuel efficiency standards. Favors plan that would see greenhouse gas emissions cut by 60 percent by 2050.
Obama: Ten-year, $150 billion program to produce "climate friendly" energy supplies that he'd pay for with a carbon auction requiring businesses to bid competitively for the right to pollute and aimed at cutting greenhouse gas emissions 80 percent by 2050. Joined McCain in sponsoring earlier legislation that would set mandatory caps on greenhouse gas emissions. Supports tougher fuel-efficiency standards.
McCain: Voted against ban on assault-type weapons but in favor of requiring background checks at gun shows. Voted to shield gun-makers and dealers from civil suits. "I believe the Second Amendment ought to be preserved - which means no gun control."
Obama: Voted to leave gun-makers and dealers open to suit. Also, as Illinois state lawmaker, supported ban on all forms of semiautomatic weapons and tighter state restrictions generally on firearms.
McCain: $2,500 refundable tax credit for individuals, $5,000 for families, to make health insurance more affordable. No mandate for universal coverage. In gaining the tax credit, workers could not deduct the portion of their workplace health insurance paid by their employers.
Obama: Mandatory coverage for children, no mandate for adults. Aim for universal coverage by requiring employers to share costs of insuring workers and by offering coverage similar to that in plan for federal employees. Says package would cost up to $65 billion a year after unspecified savings from making system more efficient. Raise taxes on wealthier families to pay the cost.
McCain: Open to helping homeowners facing foreclosure if they are "legitimate borrowers" and not speculators.
Obama: Tax credit covering 10 percent of annual mortgage-interest payments for "struggling homeowners," scoring system for consumers to compare mortgages, a fund for mortgage-fraud victims, new penalties for mortgage fraud, aid to state and local governments stung by housing crisis, in $20 billion plan geared to "responsible homeowners."
McCain: Sponsored 2006 bill that would have allowed illegal immigrants to stay in the U.S., work and apply to become legal residents after learning English, paying fines and back taxes and clearing a background check. Now says he would secure the border first. Supports border fence.
Obama: Voted for 2006 bill offering legal status to illegal immigrants subject to conditions, including English proficiency and payment of back taxes and fines. Voted for border fence.
McCain: Favors tougher sanctions, opposes direct high-level talks with President Mahmoud Ahmadinejad.
Obama: Initially said he would meet Ahmadinejad without preconditions, now says he's not sure "Ahmadinejad is the right person to meet with right now." But says direct diplomacy with Iranian leaders would give U.S. more credibility to press for tougher international sanctions. Says he would intensify diplomatic pressure on Tehran before Israel feels the need to take unilateral military action against Iranian nuclear facilities.
McCain: Opposes scheduling a troop withdrawal, saying latest strategy is succeeding. Supported decision to go to war, but was early critic of the manner in which administration prosecuted it. Was key backer of the troop increase. Willing to have permanent U.S. peacekeeping forces in Iraq.
Obama: Spoke against war at start, opposed troop increase. Voted against one major military spending bill in May 2007; otherwise voted in favor of money to support the war. Says his plan would complete withdrawal of combat troops in 16 months. Initially had said a timetable for completing withdrawal would be irresponsible without knowing what facts he'd face in office.
McCain: "Nothing's off the table" when it comes to saving Social Security.
Obama: Would raise payroll tax on wealthiest by applying it to portion of income over $250,000. Now, payroll tax is applied to income up to $102,000. Rules out raising the retirement age for benefits.
STEM CELL RESEARCH
McCain: Supports relaxing federal restrictions on financing of embryonic stem cell research.
Obama: Supports relaxing federal restrictions on financing of embryonic stem cell research.
McCain: Pledged not to raise taxes, then equivocated, saying nothing can be ruled out in negotiating compromises to keep Social Security solvent. Twice opposed Bush's tax cuts, at first because he said they were tilted to the wealthiest and again because of the unknown costs of Iraq war. Now says those tax cuts, expiring in 2010, should be permanent. Proposes cutting corporate tax rate to 25 percent. Promises balance budget in first term, says that is unlikely in his first year.
Obama: Raise income taxes on wealthiest and their capital gains and dividends taxes. Raise corporate taxes. $80 billion in tax breaks mainly for poor workers and elderly, including tripling Earned Income Tax Credit for minimum-wage workers and higher credit for larger families. Eliminate tax-filing requirement for older workers making under $50,000. A mortgage-interest credit could be used by lower-income homeowners who do not take the mortgage-interest deduction because they do not itemize their taxes.
McCain: Free trade advocate.
Obama: Seek to reopen North American Free Trade Agreement to strengthen enforcement of labor and environmental standards. In 2004 Senate campaign, called for "enforcing existing trade agreements," not amending them.