Aug. 26, 2009 -- From diagnosis to death, Sen. Ted Kennedy's battle with brain cancer was the last struggle of many during his long, eventful life.
His final years were marked by an instrumental endorsement of the nation's first black president, the escalation of a legislative health care battle he had championed for decades, and the death of his sister, Eunice Kennedy Shriver. It was during the same time that Kennedy got a close-up look at the medical system he long worked to reform while spending time with doctors fighting his devastating terminal illness.
"Over the past 10 months, I've seen our health care system up close," Kennedy said March 31, 2009, as the Senate health panel he led considered the nomination of Health and Human Services Secretary Kathleen Sebelius. "I've benefited from the best of medicine, but we have too many uninsured Americans. We have sickness care and not health care."
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The Diagnosis and Surgery: May and June 2008
Doctors found Kennedy's malignant brain tumor during tests in mid-May 2008 after the then-76-year-old senator suffered a seizure at his Cape Cod home.
The May 20, 2008, diagnosis included the senator among the ranks of 180,000 new cases of brain cancers reported each year. For patients with the most aggressive form of the tumor, median survival is less than a year; others have kept living as long as eight.
The medical community swiftly weighed in on his leadership.
"I've come to admire the man enormously in the last several years," said ABC News' medical consultant Dr. Tim Johnson on May 21, 2008. "He is a true giant in the field of those of us who care about health care reform and we want his leadership to continue."
The senator had surgery to treat his brain tumor June 2, 2008, at Duke University Medical Center in Durham, N.C. The three-and-a-half hour procedure was the first step in a treatment plan that would also include chemotherapy and radiation at Massachusetts General Hospital.
"With surgery his prognosis is better," said Dr. Jeffrey Cozzens, associate professor of neurosurgery at the Northwestern University Feinberg School of Medicine in Evanston, Ill., the day of Kennedy's surgery. "But remember that in individuals his age, despite the best treatment, half of patients are dead in one year."
Despite the odds, Kennedy laid out an ambitious to-do list in the statement announcing his decision to have surgery: "I look forward to returning to the United States Senate and to doing everything I can to help elect Barack Obama as our next president," he said.
Read more from ABC News' Medical Unit:
Kennedy's Standing O: July 9, 2008
Kennedy didn't stay away long. Just over a month after surgery, mid-chemotherapy treatments, Kennedy returned to the Senate floor.
He made an appearance to help Democrats break the deadlock and end a Republican filibuster on a bill to keep a pay cut for Medicare doctors from going into effect.
Senators from both sides of the aisle gave him a standing ovation.
"I've never seen a more moving minute then the time that Kennedy walked on the floor today," said Senate Majority Leader, Harry Reid, D-Nev.
"There was not a person who was not thrilled to see Sen. Kennedy back and looking so good," said Texas Republican Sen. Kay Bailey Hutchison.
A Rousing Speech: Kennedy's Surprise Convention Speech, August 2008
Kennedy continued to wow his colleagues and the American public that summer.
"Nothing, nothing is going to keep me away from this special gathering tonight," Kennedy proclaimed in an explosive speech at the August 2008 Democratic Convention as crowds chanted his name.
"I have come here tonight to stand with you, to change America, to restore its future, to rise to our best ideals and to elect Barack Obama President of the United States."
He also pushed his health care agenda in fall 2008 back on Capitol Hill, saying Nov. 17, 2008, that he was "looking forward particularly to working with Barack Obama on health care."
Kennedy added that he was "delighted to be back."
The Inauguration Day Collapse: Jan. 20, 2009
But the key player in President Obama's ascent to the White House unexpectedly found himself in the spotlight on Inauguration Day. Kennedy collapsed at Obama's Inauguration Day luncheon and was taken away in convulsions, suffering a seizure. Dr. Edward Aulisi, chairman of neurosurgery at the Washington Hospital Center, later said the incident was sparked by "simple fatigue."
Obama spoke about the ill senator when he returned to the lunch after escorting Kennedy out of the room.
"I would be lying to you if I did not say that, right now, a part of me is with him," Obama said. "And I think that is true for all of us. This is a joyous time, but it's also a sobering time. And my prayers are with him and his family and Vicki."
"He's awake. He's talking. He is going to be fine," Kennedy's son Rep. Patrick Kennedy, D-R.I., told ABC News from the hospital.
The senator's "Irish dander is up," said Sen. John Kerry, D-Mass., after visiting Kennedy in the hospital.
"Ted Kennedy is going to be back in the Senate fighting for what he believes in. He views this as a momentary setback," Kerry said.
Kennedy Casts Critical Vote: February 2009
The liberal lion of the Senate again returned to Washington in early February 2009 to vote on the Senate's first version of the economic stimulus bill.
"It's time that we take action now," Kennedy said entering the Capitol. "I think President Obama has demonstrated his strong commitment to making progress on these important issues and I look forward to being a part of the team."
Kennedy missed a subsequent vote on the compromise bill's final passage but reappeared in Washington on several other occasions that spring.
In celebration of his 77th birthday, the senator was honored at a tribute concert March 8, 2009, at the Kennedy Center for Performing Arts. He also dove into his work later that month, accompanied in the Senate by his Portuguese Water Dogs and working out of a special office set up for him just off the Senate floor. From inside the Beltway, Kennedy entered the fray on a bill to expand the national service corps, to advocate Sebelius' nomination as HHS Secretary, and determined as always to pass health care reform.
"It is thrilling to see you here, Teddy," Obama said in early March.
The Health Care Debate: Summer 2009
It was around late spring that Kennedy left Washington, his absence apparent as the health care debate coalesced in the summer of 2009.
Kennedy was also the only senator missing when the chamber voted to confirm Supreme Court Justice Sonia Sotomayor.
And he was missing when awarded a Presidential Medal of Freedom -- the nation's highest civilian honor -- on Aug. 12, 2009. His oldest child, Kara Kennedy, accepted the award for her father, accompanied by his other children.
Instead Kennedy spent time with family and friends in Massachusetts, sailing when possible. On Aug. 11, 2009, he mourned the death of his sister, Eunice Kennedy Shriver.
Despite his absence, Kennedy's illness didn't curb his passion for health care reform. He checked in with Obama from Massachusetts and monitored Congress' health care debate on television.
Yet his absence made a significant impression on negotiators.
"One of the biggest problems is unifying the Democrats," said Sen. Orrin Hatch, R-Utah. "And to be honest with you, he's the only person I know in the Democratic Party who could bring together its five largest groups."
Frustrated and at odds over health care reform, the Senate went home for the August recess without having struck a deal on the topic. They missed several deadlines but were hopeful a resolution would come in September.
Senate leaders also hoped that when it came time for a final vote, Kennedy would make it to Washington.
This story is a compliation of reporting from ABC News' Jonathan Karl, Kate Barrett, Dan Childs, Scott Michels, Roger Sergel, Z. Byron Wolf, Jake Tapper and Radha Chitale.