A former US secretary of state says President Bill Clinton did all he could to defeat al-Qaeda and Osama Bin Laden.
Albright said the US would have hit Bin Laden if it could
Madeleine Albright was the first of several top officials testifying before an independent commission examining the 11 September 2001 attacks on America.
She said Mr Clinton was prepared to order the capture or killing Bin Laden after the 1998 US embassy attacks.
The hearings come after ex-White House counter-terrorism aide Richard Clarke criticised the Bush policy on terror.
He accused it of ignoring the threat from al-Qaeda - concentrating instead on Iraq.
In his testimony, Secretary of State Colin Powell defended the current administration against the wider charge that it simply did not take al-Qaeda seriously enough.
Mr Powell said the Bush administration had realised the threat early on and worked out a comprehensive strategy to eliminate al-Qaeda - as well as any safe haven for terrorists, including by liberating Iraq.
Earlier, Mrs Albright said the day of the 1998 embassy bombings in East Africa had been the worst during her time in office - and days after learning that al-Qaeda had been behind the attacks, President Clinton had authorised cruise missile strikes against al-Qaeda targets.
"The president was prepared to order military action to capture or kill Bin Laden. If we had had the predictive intelligence we needed, we would have done so... and I would have strongly supported that step," she said.
She advised the current administration that al-Qaeda was not a military organisation - it was an ideology that needed to be fought.
"Al-Qaeda is an ideological virus. Until the right medicine is found, the virus will continue to spread," Mrs Albright said.
"We must be sure that Bin Laden goes down as a murderer, traitor to Islam and a loser."
She said she sympathised with Mr Bush and others who now held positions of responsibility.
She warned that, after the recent Madrid train bombings, Americans should expect more attacks on their soil.
But she also advised the Bush administration to recognise America's limits.
"If we pursue goals that are unnecessarily broad such as the elimination not only of threats but also of potential threats, we will stretch ourselves to the breaking point and become more vulnerable not less to those truly in a position to harm us," she said.
Former counter-terrorism expert Mr Clarke is due to testify before the commission on Wednesday.
White House spokesman Scott McClellan has accused Mr Clarke of political opportunism ahead of November's presidential poll.
And Vice-President Dick Cheney questioned Mr Clarke's effectiveness in running anti-terrorism efforts, citing the attacks on the US embassies in East Africa in 1998 and other incidents.
Mr Clarke served as head of counter-terrorism under four consecutive US presidents, from Ronald Reagan to George W Bush.
This is the eighth public hearing held by the bi-partisan commission, established in 2002.
The hearings - on Tuesday and Wednesday - are on "the formulation and conduct of US counter-terrorism policy, with particular emphasis on the period from the August 1998 embassy bombings [in Kenya and Tanzania] to September 11, 2001".
In his opening statement, commission chairman Thomas Kean said he regretted that National Security Adviser Condoleezza Rice had declined to give evidence.
But they had had "extensive" private meetings with Ms Rice, who had been "co-operative", he said.
ISSUES FOR COMMISSION
Congressional oversight and state of aviation security
Terrorism, al-Qaeda, and the Muslim world
Intelligence warnings against trans-national threats
Security and liberty
Border and aviation security
Former Defence Secretary William Cohen will also be testifying on Tuesday.
Mr Clinton's National Security Adviser Sandy Berger will testify on Wednesday as will
Central Intelligence Agency Director George Tenet.
A commission statement read before evidence was heard focused on US diplomatic efforts during the Clinton presidency to track down Osama Bin Laden and bring him to the US to face trial.
The Bush administration had agreed on a plan to combat Bin Laden, one day before the 11 September attacks, it said.