Although Scott Walker said he was bowing out of the presidential race to help the Republican Party rally around an alternative to “the current front-runner” -- whom he declined to name -- Walker's problem wasn't so much Donald Trump as himself.

The Wisconsin governor, a novice to national politics, was plagued by blunders even before declaring his candidacy. In February, for instance, he said his struggles with state employee unions had prepared him to take on Islamic State.

When he entered the race in July, however, he was polling strong in Iowa, which holds the first nominating contest. His Midwestern roots and his family's religious ties made him a favorite.

By Sunday, after a lackluster performance in two debates, his support had plummeted to zero in a CNN/ORC poll. His fundraising had tanked too.

Here are three areas where Walker stumbled.

His entrance into the race

Walker entered the 2016 campaign under a spotlight no candidate would enjoy -- a public tiff with his family.

When the U.S. Supreme Court ruled in June that same-sex couples had a constitutional right to marry, Walker objected.

“I believe this Supreme Court decision is a grave mistake,” he said.

The next day, Walker toned down his comments, noting that the high court's ruling was the law of the land.

But the damage was done, casting Walker not as a moderate but as one pandering to the far right.

Weeks later, as Walker prepared to declare his candidacy, his sons Matt, 21, and Alex, 20, told CNN they disagreed with his stance on gay marriage. Their mother had foreshadowed the family divide in an interview with the Washington Post.

“That was a hard one,” Tonette Walker had told the Post. "Our sons were disappointed.... I was torn. I have children who are very passionate [in favor of same-sex marriage], and Scott was on his side very passionate.”

Birthright citizenship must end

Trump, the billionaire businessman and front-runner for the GOP presidential nomination, brought the issue to the fore earlier this summer when he unveiled his immigration plan.

Several GOP hopefuls objected that ending birthright citizenship would require a constitutional amendment.

But Walker sided with Trump, who contends that a simple act of Congress would be enough to ensure that children born to mothers in the U.S. illegally would not be American citizens.

That wasn't the end of Walker's debate with himself, however. He flipped back and forth on the issue several times until eventually deciding he did not support ending birthright citizenship.

Many political observers viewed his shifting stances as amateurish. Questions began to rise about Walker's candidacy and whether he was ready for the national spotlight.

Build a wall along the U.S.-Canada border?

Walker said New Hampshire voters had asked him about putting up a wall at the Canadian border, and he was open to the idea.

His comment set off ridicule and raised eyebrows among Democrats and Republicans alike. Sen. Rand Paul of Kentucky called it a “dumb” idea. The Canadian Embassy in Washington issued a statement of objection.

To Republicans, securing the U.S.-Mexico border is vital for immigration reform, but the Canadian border doesn't inspire the same level of anxiety.

Walker ultimately was the odd man out on the issue, and soon backed down.