Gerald R. Ford once famously pointed out that the practical definition of what constituted grounds for impeaching a president (since it is only vaguely defined in the Constitution itself) consisted of whatever a majority of the House of Representatives decided were valid grounds for impeachment (Ford, on the House floor, before he became Nixon's vice president: "The only honest answer is that an impeachable offense is whatever a majority of the House of Representatives considers it to be at a given moment in history"). Likewise, it almost appears self-evident that defining what is constitutional and what is not can be similarly reduced to whatever a majority of the Supreme Court decides is constitutional, at the present time. Dred Scott was constitutional -- right up until it wasn't -- because a Supreme Court had determined it was. It took a shift of opinion on the highest court to reverse this. Again, this should all be pretty obvious to even the most causal observer of American history. Which is why, in fact, the conservative movement has focused so intently on the judicial branch for the past three decades and more. This began at the height of the anti-abortion movement during Ronald Reagan's time in office, and it continues today on the right side of the spectrum. But for some unfathomable reason, liberals have never matched this level of political fervor about judicial appointments. But now the stakes are higher than ever.

Regular readers of this column will know that in 2016, I was a supporter of Bernie Sanders. When he lost the nomination, however, I rejected all the arguments from fellow Bernie supporters about why voting for Hillary Clinton was somehow a betrayal of principle. I would occasionally argue with such friends of mine, but no matter how much they'd explain all of Clinton's faults to me, I had one fallback response: "I'm voting for Hillary because of the Supreme Court. I know full well she could massively disappoint me on any number of other issues, but I trust her to appoint a solid liberal to the Supreme Court, and that alone is enough reason to get to the polls and vote for Hillary. Period."

This argument should sound familiar to those on the right, because they have been making it to each other for many years. In fact, this very argument was extremely potent for Donald Trump himself, because no matter how nervous mainstream conservatives were about Trump on any number of other issues, there was already a freebie Supreme Court nomination hanging in the balance. This was due to some unprecedented political hardball being played in the Senate, as Mitch McConnell defied his constitutional duty and refused to allow Barack Obama's court pick to even be considered.

Such a breach in constitutionality was briefly (and rather mildly) condemned by Obama and the Democratic Party, and then they largely moved on to other subjects. The subject would occasionally come up in the campaign, but it was not all that big a selling point. It really should have been, but Democratic voters had a whole bunch of other subjects on their minds, so it's not that surprising that Democratic politicians focused on other issues as well.

When Antonin Scalia died, I pointed out what a historic chance Hillary Clinton would have had, if she had won. Not only would she get an immediate court pick, but it would flip a seat ideologically (something I had also written about, years earlier). Rather than a court split 4-1-4 (four liberals, one swing vote, and four conservatives), this would have meant a 5-1-3 advantage for the liberals. If the swing vote (Kennedy) retired at any point during the next four years, this could even mean a clear 6-3 advantage by the end of the next president's first term -- a historic power shift on the court, giving liberals a bigger advantage since they had seen since the 1970s. And that, right there, was enough for me to eagerly and happily cast my ballot for Hillary Clinton. Clinton may have had plenty of faults, but I simply could not see her nominating a dud for the Supreme Court.

In the 1980s, the anti-abortion movement decided to play a very long game. So far, this has been wildly successful for them. They have not achieved their ultimate goal (overturning Roe v. Wade), but they have chipped away at it so much that women growing up today face barriers and restrictions towards abortion that women in the 1980s would have been shocked to face. These victories for the anti-abortion movement did not appear out of thin air -- they came into being through working the political system from the bottom up, electing anti-choice candidates to statehouses and governors' mansions across the country, and then having these politicians pass as many restrictive abortion laws as they could think up. At the federal level, the anti-judicial rhetoric was turned up to white-hot levels, which essentially created a litmus test for all Republican presidents to hew to. Judicial appointment had to be anti-choice, period. Court picks were important, and none so important as Supreme Court justices.

This was all exacerbated by both sides under Barack Obama. Republicans in the Senate, also in unprecedented fashion, blocked every Obama judicial appointment possible. Harry Reid was left with a very stark choice, and he finally "went nuclear" and changed Senate rules to allow judges to be confirmed with only a majority vote -- the appointments could no longer be filibustered, up to (but not including) Supreme Court justices. When Mitch McConnell took over from Reid, instead of remaining intellectually consistent with his previous position that going nuclear was a very bad thing and should be changed back to the way it had been, McConnell instead dropped a second nuke, by declaring that Supreme Court judicial nominations could not be filibustered either. Then he defied the Constitution by refusing to act on Obama's nomination, baldly stating that no nomination would move forward until after the next election.

This was the point where liberals should have showed their outrage -- but they mostly didn't. This was where progressives should have been angrily marching in the streets -- but they didn't. For some reason, judicial appointments are seen as an esoteric and not-all-that-important thing by many lefties. Compare how liberals think and talk about judicial picks to how conservatives do, and you'll see there is a serious imbalance in the emotions the subject raises on each side of the political aisle. One side gets incensed when 5-4 decisions don't go their way, and the other barely even reacts.

And so we find ourselves where we are today. June is always the season for major Supreme Court decisions to be handed down, but this year the number of times the court has merely punted is kind of notable. The Cake Wars case was decided on a purely technical issue that had nothing to do with the underlying constitutional claim and three gerrymandering cases were likewise punted back to the lower courts with no constitutional resolution. The good news in all of these cases is that this means the fight is not over -- the real constitutional questions raised still have yet to be settled.

But at the same time, the Supreme Court has handed down a number of victories for the Trump administration, including today's ruling on the travel ban. Once again, this was a 5-4 decision, along ideological lines. Liberals will no doubt be angered by this decision, but it provides a key lesson in government and politics. If you count the sheer number of judicial victories from this single case, there were far more of them for liberals than for Trump. His first travel ban was struck down by two federal judges. Trump tried again, and lost again in court. So he tried a third time -- this time after apparently actually seeking some lawyers' advice on how to draft such an order to at least give the appearance of being somewhat impartial to religion (North Korea and Venezuela were added to the list of countries the ban would apply to). Even this attempt failed several times in the federal courts.

Right up until it didn't. Today, the Supreme Court overturned all the other rulings and handed Trump the win. This is the lesson to be learned, for liberals. It doesn't matter how many other judges rule for your side -- if you can't win at the Supreme Court then you can't win, period. Feel-good rulings from lower court judges are fun to celebrate, but they do not provide the final word on constitutionality. The high court does. Which is why it is so important.

If I were a Democratic Senate candidate right now (now there's a scary thought...), I would make this a major talking point in my campaign stump speech. The balance of power in the Senate is razor-thin right now. If control of the chamber flipped, then Democrats could block any Trump nominee to the high court, in a tit-for-tat payback for McConnell blocking Merrick Garland's nomination. "We simply must wait until after the next presidential election" Democrats could say, reminding Republicans of their own argument.

This could be crucially important, because two of the oldest justices on the highest court's bench are a liberal (Ruth Bader Ginsberg) and the swing vote (Anthony Kennedy). If either one of them either decided to step down or became somehow incapable of carrying out their duties, then Trump would get the chance to replace them. This would lead to either a 3-1-5 split on the court, or a clear 4-5 split towards conservatives. If both justices were to step down in the next two years, it could even lead to a 3-6 balance of power.

If there are six solidly conservative justices on the Supreme Court, liberals would be in for decades of losing constitutional cases such as the one decided today. Who knows what previous decisions such a lopsided court would decide to revisit? Even if they left precedents like Roe v. Wade alone, they would be setting all kinds of new precedents, with a decidedly conservative outcome.

That should scare Democrats down to their bones, but somehow the subject never really seems to come up. Judicial picks are seen as the icing on the cake when winning presidential elections. Sure, they're a nice thing and all, but they're not a real motivating factor in the voting booth or anything.

The problem with this line of thinking is that judicial appointments are a big motivating factor for the other side -- and have been, for over 30 years. Democrats are late to this party, and it shows. In recent times, Americans have come to view the court as somehow naturally balanced between four conservatives and four liberals, with one designated swing vote. This is nothing short of historical chance, though -- there is no tradition that says this balance of power must continue indefinitely. And in reality, Justice Kennedy may vote with the liberals on certain individual subjects, but overall he's got a pretty conservative view of the law. He stays with his own side a lot more than he swings, in other words.

Kennedy's advanced age, though, means that sooner or later the swing seat will be open. That will be a pivotal moment for the next two decades (at the very least) of American politics. Will we have a 5-4 liberal court, or a 4-5 conservative court? Democrats should realize the importance of this upcoming challenge, and they should make the case to their voters with fervor. "Give us a Senate majority and we promise to shut down any Trump Supreme Court pick!" should be an applause line during any Democratic Senate candidate's campaign speech. "The next Supreme Court pick will determine American politics not just for the next four years but for the next twenty years!" should likewise be a big selling point for any Democrat running to defeat Trump in 2020.

Hillary Clinton didn't stress this much in her presidential campaign. Her campaign had a lot of problems, in fact. I did not see eye-to-eye with her on any number of issues. Nonetheless, I enthusiastically voted for her. Because one thing I was fairly certain of was that I would approve (whether mildly or wholeheartedly) of any Supreme Court pick she would come up with. The stakes were high, and seeing Donald Trump get to make these picks was a horrendous concept to even contemplate. But I also knew that not a whole lot of other Democratic voters saw things in such stark terms. The Supreme Court was pretty far from the minds of many who voted for Clinton, many who stayed home and didn't vote, and even many who voted for Jill Stein as a protest vote.

That needs to change. Democrats have got to realize the importance of the balance of power on the Supreme Court outlasts any one president's other legacies. We must deal with the result for decades. Judicial picks should be a much bigger motivator on the left than they currently are. The other side already knows how important this is, and Democrats really need to catch up, unless they want rulings like today's to continue for decades to come. It's that important.

-- Chris Weigant

Follow Chris on Twitter: @ChrisWeigant