The changed attitudes, potentially the most significant since the Vietnam era, carry depressing political implications for Democrats trying to mount a campaign against President Bush in the presidential election next year.

The shift is highlighted in new polls, which show how gradual changes under way since the mid-1970s have been exacerbated by the September 11 attacks and their aftermath.

A Gallup survey shows that while Americans’ faith in political and church leaders has fallen gradually, confidence in the military has surged.

Since 1975, faith in organised religion has plummeted from 68 per cent to 45 per cent; faith in Congress has fallen from 40 per cent to 29 per cent; but faith in the military has shot up from 58 per cent to 79 per cent.

The trend is especially strong in two key groups vital to Democrat electoral success. Suburban mothers and young people have both swung sharply behind aggressive military and national security postures. Mothers, the most highly pursued group of swing voters, identified as “soccer moms” in the 1990s, have been most affected by the aftermath of September 11, the anthrax attacks and regular warnings about possible terrorist attacks, according to polls.

When asked if they were more worried about national security than before September 11, 59 per cent of men said that they were, compared with 68 per cent of women who were not mothers and 76 per cent of mothers.

Some 46 per cent of mothers believe that tightening homeland security against terrorist attacks is an extremely important problem for the Government, against 38 per cent of women without children and 33 per cent of men.

The trend played a significant part in congressional elections last November, in which the Republicans made record-breaking mid-term gains.

A Harris poll showed that the soccer mom of more peaceful times had “morphed into security mom”, according to Time magazine. In a profile of the American mother’s changed concerns, it said: “She used to say she would never allow a gun in her house, but now she feels better if her airline pilot has one.

“She wanted a nuclear freeze in the 1990s, but she now believes the Pentagon should have whatever it wants.

“Her civil liberties seem less important than they used to, especially compared with keeping her children safe.”

Similar changes are under way among the children of America’s baby-boomers, the generation for many of whom Vietnam led to a lifetime’s distrust of the military and political establishments. Their stance is the reverse of their parents. Three quarters of undergraduates said that they trusted the military to “do the right thing” either all of the time or most of the time. Two thirds supported the war in Iraq, according to a poll carried out by the Harvard Institute for Politics.

Analysts said that the changes were partly due to the speed and relative bloodlessness of the conflicts in Afghanistan and Iraq compared to the decade-long struggle in Vietnam, in which 58,000 Americans lost their lives. September 11 had also brought home the role of the military to most Americans in a way that the impersonal and largely invisible struggles of the Cold War did not.

The trend is a potential nightmare for the Democrats as they try to find chinks in Mr Bush’s political armour. Republican strategists, aided by White House officials, brushed aside much of the Democrat opposition in congressional elections last year by suggesting successfully that to oppose Mr Bush on national security issues was unpatriotic.

After the Riyadh bombings earlier this month, many of the nine candidates jostling for the Democratic presidential nomination sharpened their attacks on Mr Bush, suggesting that the Administration had let al-Qaeda off the hook while it focused on Iraq.

The polls underline that unless the Democrat candidate is trusted on national security, the party will be in serious trouble at the polls.

Joe Biden, the Delaware Senator and former chairman of the Senate Foreign Relations Committee, said he believed that Mr Bush was vulnerable next year, “but not if we don’t establish credibility on security issues”.

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