The issue is whether the European Union will invite Ukraine to sign an Association Agreement and related Free Trade Agreement at the EU summit this November in Vilnius, Lithuania.
Virtually all Ukrainian parties, including the reputedly "pro-Russian" administration of President Viktor Yanukovych and his Party of Regions, are committed to aligning with the European Union.
While not an offer of EU membership, if signed in Vilnius the AA-FTA would have historic importance in setting Ukraine's future course.
"We consider in Ukraine the signing of this agreement as the second event after the declaration of the independence of Ukraine [16 July 1990]," commented Ukraine's Ambassador to the European Union Kostiantyn Yelisieiev.
"And I would like to enforce my argument: this signing for Ukraine will be, like years ago, the fall of the Berlin Wall for Germany."
Perhaps the ambassador's reference to Germany was intended to be pointed.
While some EU member countries, such as Poland, Lithuania and Sweden, are fully supportive of the agreement, others, notably Germany, are skeptical.
Stung where it hurts -- in the purse -- by the financial crisis that has beset the European Union's less affluent southern tier, Germany is lukewarm about taking on new commitments, especially for someplace as big and poor as Ukraine.
In addition, in light of an energy partnership with Moscow some observers consider a bit too cozy, Berlin may be hesitant to offend one of its top trade partners by courting a country Russia covets.
Whatever the underlying motivations and influences, the most visible criterion for Europe's decision on Ukraine boils down to one person, former prime minister Yulia Tymoshenko, now serving a seven-year term for corruption and embezzlement for a gas-pricing deal she signed with Russia while in office.
While avoiding a direct quid pro quo that release of Tymoshenko guarantees the AA-FTA signing (or the opposite: that keeping her in prison ought to doom the agreement), officials and experts leave no doubt that Kiev's letting her go would be the most significant step they could take to secure the pact.
Even the U.S. Senate seeks to leverage possible outcomes with a nuanced resolution (Senate Resolution 165) that implies Tymoshenko's release should be a condition of the agreement without actually saying it must be.
Oddly enough, the final word in the "Tymoshenko saga" may belong to her.
Unconfirmed reports from Kiev suggest that authorities have privately indicated a conditional willingness to release her for medical treatment in Germany.
There are differing views on the state of her health. Tymoshenko's daughter, Yevgenia, says her mother is in worsening pain and urgently needs back surgery.
On the other hand, Ukrainian Foreign Minister Leonid Kozhara says she balks at independent medical tests and that "there is no evidence" she is sick.
"Ukrainian authorities want to solve Tymoshenko's issue, but she refuses to cooperate", says foreign minister.
Even medical release to Germany -- rumored for around Sep. 15, about the latest possible date to ensure a final affirmative decision for an AA-FTA signing in November -- would come with conditions.
First, Tymoshenko would have to stay out of politics for the indefinite future.
Second, she must refund hundreds of millions of dollars the Ukrainian government lost in the gas deal she negotiated with Russia.
As yet, these conditions appear to be unacceptable to her, especially repayment of the money, which not unreasonably could be construed as a tacit admission of guilt.
There are still a lot of "ifs."
If such an offer to release Tymoshenko exists, and if she finally were to agree to it, and if she is then sent abroad, that still might not guarantee the trade deal.
"Such a move would be welcome, but is not enough," a diplomat from "one of the largest Western countries" (Germany) told EurActiv.com, making it clear that sending her abroad for treatment would not be seen as sufficient to deal with EU concerns about "selective justice," an expression that usually is a codeword for Tymoshenko but which also can apply broadly to Ukraine's still evolving legal system.
The same publication said an ambassador "from an Eastern European country" (presumably one of the supporters of the offer, such as Poland or Lithuania) said that he didn't see German pressure on the Tymoshenko case as "tenable" in the long run:
"He added that the EU usually pressures countries aspiring to join the EU not to compromise on crimes or corruption cases involving high officials.
'If we had put a former prime minister in jail, the [European] Commission would have congratulated us,' the diplomat said."
Putting such irony aside, the other shoe waiting to drop if Tymoshenko refuses to accept conditional release is Ukrainian prosecutors' recent announcement that they have 90 percent completed their preparation of their case against the former prime minister for the 1996 killing of Member of Parliament Yevhen Shcherban, his wife, and two other people.
If convicted for the Shcherban killings, Tymoshenko could expect to spend the rest of her life behind bars.