In his 2006 book, The Audacity of Hope, Barack Obama wrote: "I am new enough on the national political scene that I serve as a blank screen on which people of vastly different political stripes project their own views."

On Tuesday, that proved to be a prophecy. But now his actions and deeds - his inevitable choices - will fill the screen.

Will he govern as a screen on which Congress' liberal Democratic majority will project its views, like President Bill Clinton in 1993 and 1994? Or will the views of center-left America fill the screen, as happened with Clinton from 1995 to 2000?

In other words, will Obama be led to the left by Congress, or will he lead in a more moderate direction?

If he is led, our economy will struggle under greater taxes on investors and higher-income workers. Government would take ownership of automakers. Federal domestic spending would explode. Employees of small businesses would get Medicaid-like government health insurance, paid for by taxing their employers.

Such an Obama would reduce productivity, slow economic growth and increase unemployment. He would sign bills to eliminate the secret ballot in union elections, raise the minimum wage, require businesses to provide paid family medical leave, and legalize millions of illegal immigrants.

Energy prices would rise and remain chronically high as offshore drilling was banned again. A climate bill would hand the government control over how much carbon dioxide businesses could emit, imposing heavy taxes on those that used fossil fuels.

We would go from offense to defense in the war against jihadists. We would go from fighting on their soil to fighting on ours, because Obama would withdraw our troops from Iraq, move more into Afghanistan, and close Guantanamo, releasing many of its prisoners. He would sign agreements with hostile governments that we alone would honor, allow Iran to detonate a nuclear weapon, cut the military budget, and halt implementation of a missile-defense system.

After a decade of decline, the number of abortions would again climb. They would be paid for by federal tax dollars, and restrictions such as parental consent and the partial-birth-abortion ban would be repealed with the Freedom of Choice Act.

Embryonic stem-cell research would get federal funding, as would cloning of human beings for research purposes. Same-sex marriage would get a boost, and religious liberty would come under assault with the repeal of the Defense of Marriage Act, forcing states to recognize same-sex marriages performed in other states. Obama would appoint judges who would implement this agenda by fiat.

On the other hand, if Obama chooses to lead, he will abandon or moderate the above agenda. He also would recognize an opportunity to be transformational.

A country that once enslaved blacks has elected a black man president. Who better to call heroically for an end to any remaining racial preferences?

And who better than a man from a race once treated as property to bring the nation together by recognizing the humanity of children in the womb? Who better to seek reasonable protections for those children and promote the choice of adoption?

After an intensive briefing about the threats the country faces, a moderate Obama would eschew a radically antiwar approach and an immediate withdrawal of troops, deciding that winning this war matters.

Lead or be led? Will President Obama define himself and his times? Or will they be defined for him?

Former U.S. Senator Rick Santorum is a Senior Fellow at the Ethics and Public Policy Center.