(CNN) At first glance, 2020 looks like the year where Democrats should take back the Senate majority. They have only 12 seats of their own to defend while Republicans have 22. In years past, that sort of disparity has been a recipe for success for the minority party; more targets to shoot at = more likelihood of success.

And that may be true in 2020, too! But looks -- in politics and life -- can be deceiving. And once you get beyond the raw numbers in the battle for the Senate majority, the path for Democrats looks much, much tougher.

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Start here: To win back control, Democrats need a net gain of three seats if their party's nominee beats President Donald Trump next November and a four-seat pickup if Trump is reelected. (The vice president breaks ties in the Senate, giving the party who controls the White House effective governing power in the Senate.

That's a small number -- seemingly. But, in only two of the last five elections has either party picked up more than three seats . In 2018 (Republicans +1), 2016 (Democrats +2) and 2012 (D+2), the gains all fell short of the minimum pickup Democrats need for the majority in 2020.

Then there's the actual seats in play -- which is a far smaller number than the 34 that are up for election (or reelection) in 2020. According to the Cook Political Report , a non-partisan political handicapping service, eight of Democrats' 12 seats are considered "safe" for their side, while 12 of Republicans' 22 are rated the same. Which means that the real 2020 playing field -- barring any sort of catastrophic unforeseen circumstances in the "safe" seats -- is four Democratic seats and 10 Republican seats.

And in truth, the number of truly competitive seats come next fall -- when both sides start spending millions to persuade voters -- is likely even smaller than those 14 seats. At the moment, there are really only four seats (1 Democratic, 3 Republican) that are nearly certain to produce close contests in 2020.

Alabama, where Sen. Doug Jones won a 2017 special election thanks, in large part, to Republican voters choosing the deeply politically damaged Roy Moore as their nominee. Moore spent the general election attempting to beat back allegations that he had repeatedly pursued relationships with teenage girls when he was in his 30s. Despite all that, Jones barely won, with a margin of just over 20,000 votes. Because of Alabama's strong Republican lean -- The one Democratic seat is inwon a 2017 special election thanks, in large part, to Republican voters choosing the deeply politically damaged Roy Moore as their nominee. Moore spent the general election attempting to beat back allegations that he had repeatedly pursued relationships with teenage girls when he was in his 30s. Despite all that, Jones barely won, with a margin of just over 20,000 votes. Because of Alabama's strong Republican lean -- Trump carried the state by 28 points in 2016 -- Jones immediately became the most endangered incumbent on the ballot in 2020. There's a long list of Republicans likely to run, but Rep. Bradley Byrne looks like the early favorite.

For Republicans, Colorado and Arizona are their biggest vulnerabilities.

Colorado Sen. Cory Gardner has, by all accounts, done nearly everything right in his first term but has the unfortunate distinction of being one of only two GOP incumbents up for re-election in a state Hillary Clinton won in 2016. That fact has attracted a litany of Democratic hopefuls, including two past losing statewide candidates in former state Sen. Mike Johnston (l has, by all accounts, done nearly everything right in his first term but has the unfortunate distinction of being one of only two GOP incumbents up for re-election in a state Hillary Clinton won in 2016. That fact has attracted a litany of Democratic hopefuls, including two past losing statewide candidates in former state Sen. Mike Johnston (l ost a primary for governor in 2018 ) and former state House Speaker Andrew Romanoff ( lost a primary for Senate in 2010 and a House race in 2014)

Arizona, Sen. Martha McSally hasn't actually won an election to the Senate yet. McSally was on the Inhasn't actually won an election to the Senate yet. McSally was on the losing end of a very close race for the open seat of retiring Sen. Jeff Flake (R) in 2018. But shortly after that election, Sen. Jon Kyl (R), who had been appointed to fill the vacancy caused by the death of the late Sen. John McCain (R), announced he would resign the office. GOP Gov. Doug Ducey picked McSally to fill that vacancy. Democrats seem to have united behind former astronaut Mark Kelly, the husband of former Rep. Gabrielle Giffords, as their nominee to take on McSally in 2020. Early polling suggests the race is effectively tied.

Maine Sen. Susan Collins, who, like Gardner, represents a state Clinton won in 2016. Collins, perhaps the most recognizable moderate in the Senate, has a long record of electoral success; she first won a close race in 1996 but has steadily increased her margins since -- winning with 67% in 2014. Democrats insist this race will be different -- largely because of Collins' extremely high-profile decision to be the deciding vote to confirm Brett Kavanaugh to the Supreme Court. Kavanaugh was accused of sexual assault while he was in high school and his nomination fight became the most contentious in decades. Collins' vote enraged liberals, who Only slightly less vulnerable for Republicans is, who, like Gardner, represents a state Clinton won in 2016. Collins, perhaps the most recognizable moderate in the Senate, has a long record of electoral success; she first won a close race in 1996 but has steadily increased her margins since -- winning with 67% in 2014. Democrats insist this race will be different -- largely because of Collins' extremely high-profile decision to be the deciding vote to confirm Brett Kavanaugh to the Supreme Court. Kavanaugh was accused of sexual assault while he was in high school and his nomination fight became the most contentious in decades. Collins' vote enraged liberals, who helped raise $3.6 million for her eventual Democratic opponent . Who will that be? Hard to say given that the field remains totally in flux.

Let's assume, for the sake of argument, that all four of the incumbents above lose. That amounts to a net gain for Democrats of two seats, which, even if a Democrat wins the White House, leaves them a seat short of the majority.

Where might that other pickup come from? The three likeliest suspects are Georgia, Iowa and North Carolina -- states in which freshmen senators are seeking second terms amid a recent history of competitive races between the two parties. But again, the details look worse for Democrats than the big(ger) picture.

Sen. David Perdue. But late last month, In Georgia, national Democrats put the full court press on 2018 gubernatorial nominee Stacey Abrams to challenge. But late last month, Abrams said "no." While Democrats won't walk away from the race, the party's chances of upending Perdue clearly declined when Abrams decided against a bid.

In Iowa, the situation is less dire but similar. Democrats recruited two candidates -- former Gov. Tom Vilsack and Rep. Cindy Axne -- seen as having the best chance of ousting Sen. Joni Ernst (R). Both demurred. Those no-go decisions left Democrats in the state in a bit of a lurch, with no obvious fallback plan.

Sen. Thom Tillis (R) is up for a second term. Democrats tried to convince state Attorney General Josh Stein to run but The story is the same in North Carolina where(R) is up for a second term. Democrats tried to convince state Attorney General Josh Stein to run but he removed his name from consideration in March. Democrats dream candidate -- former Charlotte Mayor Anthony Foxx -- hasn't said much about whether he might be interested.

All of these races, of course, have time to develop. Democrats will find candidates in them; the demographics and election results in all three states are simply too alluring for the party to pass. And it's also possible Democrats are able to put more GOP-held seats in real jeopardy, with Kansas' open seat and Kentucky Sen. Mitch McConnell leading that list of "definite maybes."

Still, if you look at the state of the Senate fight today, Republicans are in a far better place than a cursory glance at the map might suggest. Yes, the GOP has vulnerabilities. But no Republican senator is in more trouble than Jones in Alabama. And the second-tier opportunities for Democrats simply haven't come online just yet.

Stay tuned. Surprise retirements do happen! Recruits who have said "no" do reconsider! But unless and until those things happen, a Democratic Senate majority come 2021 looks like a long-ish shot.