BILLINGS, Mont. -- Sen. Barack Obama is on his way to Denver, following an event here where he pledged to improve mental health care for veterans and make it easier for them to get the care they deserve.

“The simple fact is we’re not doing right by our veterans – not here in Montana and not anywhere in the United States,” Obama told a crowd of about 225 veterans and military families gathered in a local park.

The Illinois senator said his administration would open more veteran clinics, hire more counselors and require mental health screening for all service members when they return from deployment.

The event comes on the same day that the Democratic National Convention’s theme is “Securing America’s Future” and will focus on military families, national security and foreign affairs.

The primetime speaker tonight will be Sen. Joe Biden, who will accept his party’s nomination for vice president.

Obama will arrive in Denver as the roll call vote including his name and Sen. Hillary Clinton’s is under way. How the vote would occur has been the subject of conversation between the Obama and Clinton camps since the New York senator announced weeks ago she would put her name in nomination.

Obama officially will become the nominee at tonight’s Democratic National Convention, but his campaign had hoped to avoid any appearance that the party was not fully united behind him.

The Illinois senator, on the last stop of his “Battleground States Tour,” went to a local gym this morning. He got in a 40-minute workout on a treadmill while watching The Today Show, which was broadcasting footage of the stage at Invesco Field, where he will deliver his acceptance speech tomorrow night.

Later he met with a Helena, Mont., native who launched a letter-writing campaign that led Montana’s governor, Brian Schweitzer, to create a task force to improve mental health care for veterans.

Matt Kuntz was inspired by his stepbrother, an Iraq war veteran who killed himself after he was less-than-honorably discharged from the Montana National Guard while suffering from post traumatic stress disorder, the Obama campaign said.

At the public event, Obama told the crowd he honors the military service of his rival, Sen. John McCain.

“We owe him gratitude for that,” Obama said. “But we don’t owe him our vote.”

The Obama campaign hopes Biden – a longtime member of the Senate Foreign Relations Committee – will boost voter confidence in the ticket in the area of national security and foreign affairs.

A CNN/Opinion Research Corp. poll taken over the weekend showed 60 percent of those polled believed Republican Sen. John McCain would better handle the issue of terrorism, compared to 36 percent for Obama.

Fifty-three percent said McCain would be better on the war in Iraq, compared to 44 percent for Obama. The others polled said neither or no opinion.

They gave Obama higher marks than McCain on the issues of the economy and health care.

The poll surveyed 909 voters nationwide, and has a margin of error of 3.5 percentage points.