NEW YORK _ The first day of the Republican convention featured the Army fight song, pictures of fighter jets taking off, a pep talk from a firefighter union boss, and one underlying message: The Sept. 11, 2001, terrorist attacks and the war in Iraq are inseparable.
A link between Iraq and Al Qaeda was crucial to building support for the Iraq War, but has since been disputed and separated in the public mind. Many polls suggest strong support for President Bush's efforts to fight terrorism, but far less support for his policies in Iraq.
The combination of setbacks in Iraq --an unexpectedly vigorous insurgency, criticism from allies, difficulty establishing a democratic government -- has left Bush politically vulnerable. Yesterday, the Republicans set out to convince America that it was all necessary.
The convention planners, who promised an even sharper focus on a single message of the day than at last month's Democratic convention in Boston, sought to reforge the link between Sept. 11 and the Iraq war in a multimedia blitz of speeches, videos, tributes, and celebrity endorsements.
''It was here in 2001 in Lower Manhattan that President George W. Bush stood amid the fallen towers of the World Trade Center and said to the barbaric terrorists who attacked us, 'They will hear from us,' " declared former New York mayor Rudolph Giuliani, in the day's dramatic high point. ''They have heard from us. They heard from us in Afghanistan, and we removed the Taliban. They heard from us in Iraq, and we ended Saddam Hussein's reign of terror."
Giuliani's implication of a direct Iraqi role in the attacks on New York and Washington went beyond Bush's and Vice President Dick Cheney's contention that Iraq collaborated with Al Qaeda, but was not involved in the attacks.
But even the lesser claim of a working relationship between Iraq and Al Qaeda has been disputed by the commission investigating the attacks and by a yearlong investigation of the Senate Intelligence Committee.
Bush and Cheney have expressed some disagreement with the findings of both probes and have sought to connect Iraq and Sept. 11 in other ways, by suggesting that the decision to attack Iraq was a way of applying the lessons of the attacks.
Yesterday, the fights against Al Qaeda and Hussein were merged into a single post-Sept. 11 war on terror, celebrated in a music video tribute to the armed forces, in the testimony of survivors of Sept. 11, and in speeches by leading Republicans, including Arizona Senator John McCain.
After vividly recreating the atmosphere of Sept. 11, 2001 (''that bright September morning"), McCain called on all Americans, including his friends in the Democratic Party, to join the fight against weapons of mass destruction. And McCain insisted that invading Iraq was a ''noble" cause in that war.
''The central security concern of our time is to keep such devastating weapons beyond the reach of terrorists who can't be dissuaded from using them by the threat of mutually assured destruction," McCain said. ''We couldn't afford the risk posed by an unconstrained Saddam in these dangerous times."
The extent to which the electorate accepts McCain's argument could go a long way toward determining Bush's fate.
After reaching a high of roughly 70 percent after the fall of Baghdad last year, support for the Iraq war has dropped sharply; in some national polls, a majority believe it was a mistake to go to war.
Now, even after a modest Bush revival in polls, support for the president's Iraq policies lags behind support for his efforts to combat terrorism. In a Fox News poll released last week, Bush led Democrat John F. Kerry in fighting terrorism, 50 percent to 34 percent, but led him on Iraq policy by only 45 percent to 40 percent.
Andrew Kohut, director of the nonpartisan Pew Research Center, explained, ''We would never have had support for the war in Iraq without the belief that it was part of the war on terrorism."
Insisting that war in Iraq is a necessary response to the post-Sept. 11 war on terror ''is one of the things they need to say to get the public to accept the cost and excuse the errors," he said.
Yesterday, with two of the party's most credible moderates vouching for Bush's leadership, and music and videos blurring the lines between Afghanistan and Iraq, the GOP was at its most persuasive.
''Only the most deluded of us could doubt the necessity of this war," said McCain, comparing Bush's actions after Sept. 11, 2001, to Franklin Delano Roosevelt's actions in World War II. ''Like all wars, this one will have its ups and downs. But we must fight. We must."