This has been a great week for Senator John McCain. Being endorsed by major newspapers, as well as 2000 Democratic vice presidential nominee Senator Joe Lieberman, John McCain has reasserted himself as someone who could win it all.

There are reasons for this success. His continued push on ending the disgrace of earmarks, balancing the budget, expanding the military and transforming entitlements still resonates. And the Iraq turnaround has turned around Mr. McCain’s chances.

The fact is that Senator McCain’s credentials to be commander-in-chief are the strongest of anyone running in either party. Only Rep. Duncan Hunter of California comes close to Mr. McCain’s military expertise. After all, the president’s primary duty is to protect the American people.

Many originally thought that the GOP nomination was Mr. McCain’s for the asking, motivating liberal activists to attack him early on in the campaign season.

Then the senator ran into two challenges. The first was his connection to the Iraq War. Deriding the Iraq troop surge as the Bush-McCain surge, Democrats tied the frustrations from Iraq around the senator’s neck. Now the incredible progress on the ground in Iraq has made that association an asset. Mr. McCain long pushed for what has now become a winning military strategy.

But the biggest challenge Mr. McCain faced — and continues to face — is that frankly, some Republicans just don’t trust him. It goes deeper than policy disagreements on issues like campaign-finance and immigration. Many Republicans believe that Mr. McCain does not share their values or priorities. Some conservative leaders believe Mr. McCain’s team has been dismissive, or even contemptuous.

Early in this cycle Senator McCain and his strategy team clearly underestimated just how deep the distrust and disconnect ran in many circles. Even if he wins the nomination in a divided field without these people, he cannot win the general election without getting their support. Those on his team who thought all these people would simply “come around” don’t understand large segments of the base who would rather stay home than vote for someone they consider hostile to what they hold most dear.

John McCain needs to solidify that base.

Politics is about relationships. The senator has done some work to build or repair these relationships. While the late Reverend Jerry Falwell was only one influential leader among the Christian Right, the fact that Mr. McCain reached out to him was seen as an olive branch by some. And the Senator’s appearance before an NRA gathering was a positive move toward another major bloc that he often antagonized.

But many of these relations are so bad that it’ll take a lot more than isolated gestures. He needs to reach out and open meaningful dialogues. Senator McCain should spend time with the leaders of these organizations and movements, and specifically address their concerns, even if it’s only to respectfully disagree on some points. Additionally and perhaps even more importantly, he needs to try bringing more people representing these conservative elements of the Reagan coalition onto his team so that he can represent the broad spectrum of the Republican “big tent.”

Specifically, the one issue where Mr. McCain could benefit immensely by taking a clear stand is judges. Many people misunderstand the senator’s membership in the Gang of 14 to be compromising on judicial appointments, when actually his moves secured the confirmation of some of our finest appellate judges, some of whom could be Supreme Court nominees. Mr. McCain should do what Rudy Giuliani has done, making judges a stump speech issue and putting conservatives at ease on what the number one issue is for many of them.

But Mr. McCain needs more help than just strengthening his stand on judges to energize the base. He needs a running mate who will excite those with reservations. His record on the issues is good enough for pro-lifers, Second Amendment supporters, the Christian Right, and philosophical conservatives to be eager for him if his running mate is an outspoken advocate for conservative social causes.

Enter Mike Huckabee. He is the only major candidate to be a longtime leader on all the social issues of life, marriage, faith, and the Second Amendment. Governor Huckabee has become a phenomenon representing the dreams of millions of social conservatives, and whose presence on the ticket would light a fire in those camps to enthusiastically work for Mr. McCain.

Of course, Mr. Huckabee will vigorously assert that he’s running for president, not vice president. And looking at his current standing in Iowa and the national polls, he may well make that happen. He’ll no doubt say that people should be asking whether he’d be willing to take Senator McCain as his running mate, not the other way around.

The other major candidates are surely still contenders for the nomination, while other conservatives could make good running mates. Mr. Giuliani, especially, could yet recover and take the prize. We’ll know soon enough.

John McCain’s challenges are largely of his own making, as are his strengths. The next couple of weeks will be fascinating.