But our gratitude for life and liberty should also serve as a reminder that what we were working so hard to achieve these past few years still very much hangs in the balance. And it is up to each of us to continue that fight. Our participation as citizens of the United States does not end once we’ve pulled the lever in the voting booth. That ballot is just the beginning.

We are now living in a nation controlled by a Democratic Party committed to cutting the budget for our national defense, raising taxes and nibbling around the edges of our personal freedoms in the hopes none of us notices. Democrats will do it through regulation in the executive branch, legislation in Congress and rulings from the judiciary.

This activity will be taking place during a time when we know that somewhere in the world our worst enemies either have, or are trying to get their hands on, the most dangerous weapons known to man. Small rogue nations are developing nuclear weapons to threaten us and our allies. Some large nations are engaged in massive military buildups, while others seek to take advantage of our weakened financial condition to wage a kind of economic warfare that is only now possible because of our global economy. And all the while the greatest economic threat of our lifetime and our children’s lifetime—the bankrupting of our entitlements systems—will be ignored.

It’s not a pretty picture, is it?

But if the time I spent traveling around America the past 18 months has given me anything, it is hope. And it if has confirmed anything for me, it is this: America remains the greatest country in the history of the world, and our citizens who care about our nation’s founding values—freedom, free markets, respect for life and the rule of law—will not stop defending these values as much as some of our fellow citizens and leaders might wish they would.

The Democrats and their P.R. machine known as the “mainstream media” liked to talk about 2008 as an election about “change.” Well, let me tell you, by their nature, every election is about “change.” In fact, responsible change is the essence of conservatism. We must change in order to preserve what is best about our country. We have always been able to accommodate constructive change without turning our back on our first principles.

But now, we should admit that we didn’t do a good enough job of holding our elected officials accountable over the past few years when spending got out of control, and we seemed to lose sight of the policies grounded in our first principles. It’s going to be a high price we pay, but we must not lose sight of what we must be doing now: fighting for conservative change we want today—and tomorrow.

We are going to have to use every tool we have—grassroots organizations, think tanks, magazines, talk radio, the Internet—while building new institutions to blunt the efforts of a left-wing establishment that appears willing to use uncertainty to impose an agenda that would never see the light of day in normal times.

The challenge will be to fight the Democratic instinct to let government meet every need and solve every problem and to divide our nation by class and race, while also laying the groundwork for the kind of historic mid-term election we achieved in 1994.

We gained those victories with a focus on innovative, free-market, pro-freedom, policy solutions to issues like welfare reform, promising to cut spending and balance the budget, and recruiting a host of talented, young (and perhaps not-so-young) men and women willing to step into the arena and run for office.

We have the formula—a conservative formula—that has worked before and will surely work again. It is grounded in our first principles. It’s time we moved past the recriminations and seven stages of grief. It’s time to look ahead, to stay united and to defend the values that we know must endure if our nation is to do the same.

Although Americans are used to Labor Day campaign kickoffs, this year’s back-to-back political conventions meant exposure to more than the usual number of partisan promises of a bright future and excoriation of the opposition.

So, while most of us who address the national conventions like to think our words will make all the difference for our party and the great American who is our nominee, in reality our speeches usually just blend into a kaleidoscope of impressions the public takes from the week’s events.

That is why, in my own convention speech, I tried to tap into a sentiment already established in the public mind. I talked about John McCain’s remarkable and heroic record as a POW. But I also talked about the John McCain that I got to know while sitting in the desk next to his on the floor of the U.S. Senate.

Citing any senator’s record, however impressive, may or may not electrify convention delegates. But it was my way of laying down a marker on behalf of a theory I have about both conventions and campaigns in general. Even amid a convention’s staged bedlam and overly hortatory speeches, voters do pick up information that develops into lasting impressions that count for something on Election Day.

The pundits and the political class sometimes underestimate the extent to which the public, in its subliminal but thorough way, collects data and makes informed electoral decisions. In a broader sense, voters carry into the polling booth this ultimate question about presidential candidates: “Who do I trust to make the right decision?”

Key issues for voters in this election will be freedom and national security, and here their impressions will be vivid: rogue nations with rapidly developing nuclear capabilities, nuclear-armed nations in volatile regions such as India and Pakistan, traditional nuclear powers such as Russia flexing their muscles and threatening the liberty and stability of those around them, and China building up its military in a way that suggests it wants to beat the United States in more than gold medals.

Here McCain makes his own vivid impression. His record shows that, early on, he understood the ominous intentions of Russia’s leaders, made the Iranian mullahs fear him and foresaw the need for a troop surge in Iraq, which, along with his own military service and longtime Armed Services Committee membership, add up to real national security experience.

By contrast, voters struggle with his opponent’s virtually nonexistent record on these issues. It comes down to a common sense decision that says: With national security traffic so heavy, this is not the moment to turn the car keys over to a teenage driver. Presidents don’t have time for drivers ed.

On the economy, voters have the same impression of McCain that I had on the Senate floor, where he fought plenty of fiscal battles. Some he lost. Some he won. Sometimes his colleagues liked him for it. Sometimes they most decidedly did not like him for it.

But the impression left with voters is, again, one that contrasts with his opponent’s. The McCain record shows he often stood alone in understanding that long-term prosperity of the American people requires us to stop wasting and spending the birthright of the next generation. And he knows, as his opponent does not, that you don’t make the American people prosperous by making the government richer and that, in an economic downturn, you don’t impose the largest tax increase in American history.

Finally, an issue McCain has asked me to help his campaign with — the federal judiciary — is one that disturbs voters to the point of having enormous electoral possibilities. The federal judiciary is the Democratic Party’s vehicle of choice to enact policies that could never see the light of day if they were required to go through the democratic process. And that party now talks about electing a supermajority in the Congress that, along with the most liberal president in our lifetime, would allow them to change the face of America without enacting one piece of legislation — a change that would take us a generation to rectify, if we ever could.

McCain has chosen to make this issue a priority because he thinks the public worries about a Supreme Court lost to liberalism for our lifetime, and that it cares about the appointment of federal judges who will follow the law and the Constitution and not remake it along the lines of their own policy preferences.

McCain’s opponent has carefully worked his way up the political ladder, guided by no discernible political principles except adherence to party positions — which he has showed a willingness to change if the political winds blow too strongly against them. By contrast, McCain’s life and career exemplifies courage, sacrifice and leadership.

Put simply: Others talked about reaching across the aisle and reconciling differences; John McCain did it. Others went along with pork barrel spending and getting the political benefit from it; John McCain fought it. Others wanted to declare defeat and cut and run in the central front of the war on terrorism; John McCain fought for a strategy that would ensure victory. Others gave lip service to reform; John McCain actually made it happen.

So impressions matter in politics — as do the facts and the record that create those impressions. Through all the convention hoopla and focus on the Electoral College horse race, then, the impressions of John McCain come through. Impressions of the same John McCain who lit up the political atmosphere last week with a startling and brilliant choice for running mate, the impressions of a lifetime record summed up by a word: leader. And a title: Mr. President.