WASHINGTON, Oct 25: Buoyed by a huge fund-raising advantage and a steady lead in national polls, Democrat Barack Obama began his closing arguments for the presidency on Saturday with an optimistic message that his economic policies would bring better days for hard-pressed middle-class Americans.

Republican John McCain sought to raise doubts about his rival’s tax policies and readiness to be commander in chief as he fought desperately to stem losses in traditionally Republican-leaning states on the next-to-last weekend of the testy presidential race.

Both campaigns focussed on western states on Saturday. Once reliable Republican territory, much of the West has seen its politics and demographics shift over the last decade as the Hispanic population, which tends to favour Democrats, has grown. Three states considered still in play to varying degrees --- Nevada, Colorado and New Mexico --- could be vital if the electoral math gets tight.

But time is running out for McCain who acknowledges that he is trailing in the polls and needs to mount a comeback.

A Newsweek poll of registered voters showed Obama with 53 per cent to McCain’s 40 per cent. The poll found Obama leading in every age group and among men as well as women, and even holding a slim 46-to-44 per cent edge among working-class whites.

The telephone poll, conducted from Oct 22-23 with a margin of error of 3.6 percentage points, also found that 62 per cent of those surveyed had a favourable view of Obama.

Obama resumed his campaign in Nevada on Saturday with rallies in Reno and Las Vegas before holding one at night in Albuquerque, New Mexico, and plans to head to Colorado on Sunday. The Democrat put aside political events on Thursday night and Friday to spend time with his grandmother in Hawaii, whom he described as gravely ill.

Obama’s emphasis is on getting supporters to vote early --- locking in votes that might not materialise if people get busy or stay home because of bad weather on election day.

McCain, after his three stops in Colorado on Friday pushed hard in New Mexico on Saturday. He held rallies in Albuquerque and in Mesilla.

The Republican candidate heads to Iowa on Sunday, looking to make up for some lost ground in a Midwestern state his campaign aides argue is closer than the public polling shows. His running mate, Alaska Gov Sarah Palin, was in Iowa on Saturday.

The Democratic vice presidential candidate Joe Biden was campaigning on Saturday in Virginia, where polls show Obama leading in a state last won by a Democratic presidential candidate in 1964.

Obama, a senator from Illinois, unveiled a two-minute TV ad that asks, “Will our country be better off four years from now?

“At this defining moment in our history, the question is not, ‘Are you better off than you were four years ago?’ ” Obama says in the ad. “We all know the answer to that.”

Without mentioning McCain, the ad promotes Obama’s economic policies while saying that Obama will work to end “mindless partisanship” and “divisiveness”.

The length of the ad, which will start airing in key states on Sunday, highlights Obama’s fundraising superiority.

McCain, a senator from Arizona, used his weekly radio address on Saturday to attack Obama on taxes.

The Republican National Committee, meanwhile, released a TV ad questioning whether Obama has the experience to be president.—AP