"My greatest concern for our country is the direction of the Supreme Court. If there is one reason to vote, this is it."

This is how Cissie Graham Lynch, granddaughter of Billy Graham and daughter of Franklin Graham, explained her endorsement of Trump when she went on Fox News.

She was not alone. For evangelicals the state of the Supreme Court in America dominated their thinking as they weighed a longstanding support of Republicans with a nervousness about Trump's horrific rhetoric. But the court won out. Evangelicals overwhelmingly backed Trump by four to one.

Clearly it was not not the only issue. But it was very important.

Wayne Grudem, Franklin Graham, Eric Metaxas, Jerry Falwell and James Dobson all cited the court in justifying their support for Trump.

The Supreme Court in America hangs in the balance. Out of nine seats, four are liberal leaning, four are conservative leaning and one is empty.

It is the ultimate judge involving all laws of Congress and in administrating the highest law of all – the constitution. It has the power to check the actions of the president and Congress if they are deemed to go against the constitution.

Made up of nine justices, the appointments are all lifetime positions. There is no limit to how long they can stay unless they are impeached, which last happened in 1805. Since 1970 the average tenure has been 26 years.

So it holds an immensely powerful position in the US legal system. But it is also highly political.

Supreme Court Justices are first nominated by the president but then have to be appointed by the Senate. Presidents are likely to suggest judges who are sympathetic towards their political leaning. Although the judiciary is supposed to be non-partisan, in reality it is nearly always neatly divided along party lines. It is difficult to find a judge in the States whose legal judgments aren't influenced by his or her political convictions.

In the current cohort John Roberts, Samuel Alito, Clarence Thomas and Anthony Kennedy lean consistently to the right, although Kennedy is slightly more unpredictable. Ruth Bader Ginsburg, Elena Kagan, Sonia Sotomayor and Stephen Breyer tend to be more liberal.

So the ninth and final is crucial in tipping the balance one way or another. The President has control over whom to nominate and will choose someone who is sympathetic to his politics.

This can prove complicated when the president is from one party but the Senate is controlled by another, as is the case currently.

Supreme Court Justice Antonin Scalia, an arch conservative, died in February 2015. It is the president's constitutional responsibility to nominate a replacement and Obama duly suggested Merrick Garland in March 2015.

But the Senate judiciary committee, which decides whether to give the go-ahead for a vote in the wider Senate, refused to hold any hearings. They said because an election was approaching, the decision should be postponed until there was a new president. "The American people should have a voice in the selection of their next Supreme Court Justice," said the Republican Senate Majority Leader Mitch McConnell.

Together with Senate Judiciary Committee Chairman Chuck Grassley, McConnell blocked Obama's nomination.

While ethically dubious it is technically legal and the ninth post on Supreme Court remains empty without Senate approval.

With Trump's election this week the Republicans now hold both the White House and the Senate, paving the way for a conservative appointment tilting the balance of the court towards the right.

A conservative dominated court could have serious implications. Simply put, "if you have a conservative court, you are going to have more conservative decisions," said Kerri Kupec, a lawyer with the Alliance Defending Freedom, a conservative Christian legal group involved in religious rights cases.

First, a number of Obama's key initiatives are tied up in legal challenges and are now more likely to lose. These include his signature 2010 healthcare law, his plan to combat climate change, his executive action on immigration and his transgender rights policy.

A major upcoming issue is whether business owners who oppose same-sex marriage can object on religious grounds to providing services to gay couples. One dispute concerns a baker in Colorado, while another involves a florist in Washington state.

On top of that a conservative court would probably be favourable toward gun rights, sceptical of abortion and supportive of the death penalty when it came to legal cases involving these issues.

But with three judges 78 or older including 83-year-old liberal Ruth Bader Ginsburg, whom Trump called on to resign in July after she called him a "faker", Trump's administration could make further appointments.

Fellow liberal Stephen Breyer is 78, while conservative Anthony Kennedy is 80.

If these three retired or died in the next four years the Trump administration appointments could dominate the court for decades to come.

Trump has already issued a list of 21 judges, mainly federal judges appointed by President George W Bush and state court judges, he said he would consider to fill Scalia's vacancy. All have conservative credentials on such issues as abortion, birth control and gun rights.

The case that could be affected soonest by Trump's win involves transgender rights. The court on October 28 took up a case concerning a female-born transgender high school student named Gavin Grimm, who identifies as male and sued in 2015 to win the right to use the school's boys' bathroom. Grimm is backed by the Obama administration.

No date has been set for the argument in the case. The court could potentially delay acting until it has nine justices.

A ruling could resolve similar litigation around the country over an Obama administration directive saying schools should allow transgender students to use the bathroom of their choosing.

Trump has said he would rescind the directive. He also has said he would rescind Obama's executive action to protect millions of immigrants in the country illegally from deportation and give them work permits, which was put on hold by the courts while the administration fights to revive it.

Trump is also expected to overturn major regulations put in place under Obama, including the Clean Power Plan to curb greenhouse emissions mainly from coal-fired power plants. That process takes time, meaning the Supreme Court could potentially rule on a legal challenge to the Clean Power Plan before Trump can dump it. The case is pending before an appeals court in Washington.

White evangelicals voted for Trump largely based on his promises over the Supreme Court. And it is plausible Trump could make up to four appointments to the court in his time as president.

The evangelical gamble paid off. It looks like they have control of the court for the foreseeable future.

Additional reporting by Reuters.