The Issue
Insurance coverage for abortions in the health care legislation.

The Fight
Abortion opponents want tight restrictions on coverage for abortions, including a ban on coverage for any health plan that is purchased even partly with new federal subsidies intended to help moderate-income Americans buy insurance. Advocates for abortion rights acknowledge that Congress will not allow federal money to be used to pay for abortions, but they do not want any restrictions beyond those in existing law, which bar the use of tax dollars for abortions with exceptions for rape, incest or the mother’s health.

The House Bill
The health care legislation approved last month by the House includes tight restrictions on insurance coverage for abortions. The restrictions were included in an amendment, sponsored by Representative Bart Stupak, Democrat of Michigan, that was approved just before final passage of the bill after negotiations between abortion opponents and supporters of abortion rights broke down.

The Senate Bill
The bill now being debated on the Senate floor includes language intended to preserve a federal law, known as the Hyde amendment, which bars the use of federal dollars for abortions except in rare cases. The Senate bill would require that at least one government-approved health plan in each state cover abortions and that at least one government-approved health plan in each state not cover abortions. Only premiums paid privately by beneficiaries could be used to pay for abortions. Insurance plans would be required to segregate that money to ensure that no tax dollars are used for abortions.

The Debate
Senator Ben Nelson, Democrat of Nebraska and an opponent of abortion rights, is preparing an amendment that would largely adopt the Stupak language as part of the Senate bill. To do so, Mr. Nelson and his supporters will need to win the votes of at least 60 senators. Liberal Democrats, who support abortion rights and vehemently oppose the Stupak language, are confident they have the votes to defeat the Nelson amendment. Debate is expected to begin Monday afternoon.

Lawmakers to Watch
Mr. Nelson is leading the effort by abortion opponents in the Senate. Senators Barbara Boxer, Democrat of California, and Barbara A. Mikulski, Democrat of Maryland, are among the leaders of those defending abortion rights. Among the Democrats expected to back Mr. Nelson’s amendment are Senators Kent Conrad and Byron Dorgan of North Dakota and Robert C. Byrd of West Virginia. Senator Bob Casey of Pennsylvania, a liberal and a prominent Catholic who opposes abortion rights, could emerge as a broker of a deal. Also keep an eye on the Senate majority leader, Harry Reid of Nevada, who has voted in the past to restrict abortion rights but is under a lot of pressure by the liberal wing of the party and faces a tough re-election campaign next year. Republicans expected to oppose the Nelson amendment include Senators Olympia J. Snowe and Susan Collins of Maine.

Lobbying
Catholic bishops and other opponents of abortion are urging senators to support Mr. Nelson’s proposal. Planned Parenthood and other abortion rights advocates view the Stupak language as a major threat and are mobilizing large networks of their members.

The Bottom Line
Insurance coverage for abortions is typically not the top priority of the millions of uninsured Americans, who need benefits to cover basic, everyday health concerns. But politically the health care legislation cannot be finalized without a hard-fought compromise on this deeply divisive and emotional issue.