These are difficult days for President Bush and comparisons with Vietnam are being made.
The attack on the Chinook helicopter brings back too many bad memories.
Even the doyen of Washington's political correspondents, David Broder of the Washington Post, is now referring to the V word, albeit in the context of quoting someone else.
He reported recently on an event about President Lyndon Johnson, whose career was destroyed by Vietnam.
Defeating Iraqi resistance should not be beyond the capability of the US
One speaker, the Harvard historian Ernest May, said that Iraq was "eerily reminiscent" of the early days of Vietnam, adding however that it was not clear whether the "crumbling" in Iraq would be as pervasive as that in South Vietnam.
And that is a major point. Like generals, analysts often simply re-fight old wars when looking at a new one. In South Vietnam, the US faced not only an indigenous insurrection from the Viet Cong. It faced the North Vietnamese regular army. It was also propping up a corrupt establishment.
'Likely to win'
In Iraq, there is no external force, beyond perhaps the "foreign fighters", whom US and British officials tend to blame for some of the troubles.
In theory, defeating the Iraqi resistance should not be beyond the capabilities of the US and British troops, as long as they are helped by the Iraqi security forces.
"By the standards of counter-insurgency warfare, most factors, though admittedly not all, appear to be working to our advantage," Michael O'Hanlon, a military analyst at the Brookings Institution in Washington, told a congressional committee on 29 October.
"While one would be mistaken to assume rapid or easy victory... we are nonetheless quite likely to win."
Poll ratings down
The latest casualties have brought Mr Bush's poll ratings on Iraq to below 50% for the first time. An ABC-Washington Post poll taken on 1 November, before the attack on the helicopter, gave him a 47% approval figure compared with 51% disapproval.
His overall approval ratings as president stood at 56% in favour and 42% against.
There is, therefore, a particular problem for Mr Bush over Iraq and until and unless casualty figures are reduced, these problems will continue and may get worse.
At the moment, though, Mr Bush shows no signs of weakening.
"Our will and resolve are unshakeable," White House spokesman Trent Duffy said.
When spokesmen talk about "unshakeable will", you know things are not going well.
But the opposition Democrats do not seem to be capitalising much on the presidential problems.
Call for withdrawal
The only one of them to vote against the congressional resolution approving the war, Ohio Representative Dennis Kucinich, has called for withdrawal.
"This disastrous mission must be ended before any more lives are lost... it is time to bring our troops home," he said.
The other candidates are floundering around, criticising the administration without daring to call for withdrawal.
Former Nato commander Wesley Clark said: "We were misled into this conflict without a real strategy for success."
Outside help suggested
And Missouri Representative Dick Gephardt called for outside help.
"We cannot solve this problem alone," he said.
He added that the US should talk to foreign leaders, "treat them with respect and ... get the help that we should get from our friends."
Easier said than done, of course, given the reluctance of anyone else to get involved at this stage.
Two leading senators in the foreign affairs field, Jo Biden, a Democrat and Richard Lugar, a Republican, have called for more troops to be sent.
But more troops might simply mean more targets and the US army and its reserves are already stretched tightly. Mr Bush will be reluctant to send reinforcements, unless the military asks for them.
The weakness of his opponents gives Mr Bush a window during which he can work to bring things round in Iraq. His main test will come next year as the election campaign gathers pace.
The American public still seems to be at the stage of putting its shoulder to the wheel. One should not forget that it took years for the American public to give up on Vietnam.
But Mr Bush needs to show some successes. He faces important decisions on the pace of "Iraqi-isation" and the handover of power.
Local security forces have to be strengthened. Intelligence needs to be improved. Faith in a political process has to be created.
Iraq has not proved to be like Germany and Japan after World War II.
Those countries were destroyed, their armed forces had surrendered. The German population accepted the occupation and no American troops lost their lives from hostile action.
Some have gone back in history to draw comparison with the Philippines in the early 20th Century when the US took over from the Spanish after the Spanish-American war.
It is not a very happy comparison. When the Americans arrived, they were welcomed by the people who had been fighting for their independence from Spain. But the locals then became afraid that an occupation, not a democracy, was the American aim and conflict broke out.
It took several years for the country to be pacified and then only after brutal American repression. In one incident, in 1906, there was a massacre of 600 people and more by American troops who fired down into a volcanic basin. The action was led by US General Leonard Wood, who later nearly became a presidential candidate.
The writer Mark Twain described the war as "a mess, a quagmire from which each fresh step renders the difficulty of extrication immensely greater."
In Iraq, the idea is to do it differently.