The struggle in the U.S. Congress over healthcare reform has led to speculation that Democrats' honeymoon with Democratic President Barack Obama is coming to an end, six months after he took office.

But if the Democratic-controlled Congress and the president manage to iron out differences and enact healthcare reform this year, Obama will have fulfilled the most important promise of his 2008 campaign -- the revamping of a $2.5 trillion industry that has left 46 million people without medical insurance and costs escalating for those with coverage.

Even Republicans privately concede that so far Obama has been nearly unbeatable, although he has been roughed up over his drive to close the Guantanamo Bay, Cuba, prison for terrorism suspects. Beyond that it's been a lopsided tally.

Here is major legislation adopted since Obama took office:

* In February, Congress approved $787 billion to stimulate an economy deep in recession. Obama began lobbying for fast passage of the legislation almost immediately following his November, 2008 election.

* Obama signed a new law that allows the Food and Drug Administration to regulate the advertising, marketing and manufacturing of tobacco products, which is considered the number-one cause of preventable death in the United States.

* Consumer protections are in place as a result of legislation clamping down on financial institutions' rules on credit cards. The new law targets unfair rate increases, abusive fees and penalties.

* Congress embraced many of Obama's fiscal plans when it passed a 2010 budget blueprint. But the congressional budget rejected Obama's move to extend a tax credit for middle- and low-income workers beyond 2010 and ignored his request for more money for the $700 billion financial bailout program.

* Congress gave Obama $80 billion to ramp up the war in Afghanistan and wind down the war in Iraq, another major campaign promise.

* The House approved a cap and trade bill to reduce industrial pollutants blamed for global warming. While the measure would allow companies to trade pollution permits with each other, Obama wanted the government to initially sell those permits to firms. Instead, about 85 percent would be given to companies under the bill. The legislation, one of Obama's top priorities for 2009, faces an uncertain fate in the Senate.

* The Senate backed Obama's demand that funds be cut off for producing the F-22 fighter jet and a new engine for the F-35 Joint Strike Fighter. While the House might insist on the funds, the Senate's vote was a step forward for Obama's drive to end what he sees as wasteful Pentagon spending.

* Expanded healthcare coverage for children in low-income families. The measure was enacted after former President George W. Bush vetoed earlier bills.

* The Senate is poised to confirm Obama's first appointment to the Supreme Court. Sonia Sotomayor skated through Judiciary Committee confirmation hearings and barring any unexpected developments, the first Hispanic will be sitting on the highest court when it convenes in October.

* Other Obama victories include legislation to prevent some home foreclosures, improve women's wages and conserve wilderness areas.

(Reporting by Richard Cowan in Washington, editing by Vicki Allen)