(Bloomberg) — When Benjamin Netanyahu addresses Congress
on Tuesday, the Israel prime minister will call for a halt to
President Barack Obama’s emerging nuclear deal with Iran, a step
viewed by some as a bold act of principle and others as crude
electioneering.

Since accepting Republican House Speaker John Boehner’s
invitation in January, Netanyahu has clashed repeatedly with
Obama, who said he would not be welcome at the White House
during the trip. The 65-year-old leader refused appeals from
Democrats to cancel the speech, saying the threat to Israel from
a nuclear Iran is so great, he can’t be bound by ordinary
protocol.

Even some frequent supporters disagree, arguing that he is
endangering the state’s main alliance.

“No matter how Churchillian Netanyahu may be when he
speaks, no matter how powerful his words, he misunderstands the
dynamics in Washington,” said Gil Troy, an American-Israeli
historian and commentator. “With each added insult, we’re going
from the usual spat to a really serious and game-changing
challenge.”

U.S. Secretary of State John Kerry on Sunday attempted to
ratchet down tensions, saying on ABC television that Netanyahu
was always welcome to speak in the U.S. and the allies share the
goal of barring an Iranian nuclear program.

Netanyahu’s appeal will also be addressed to Israelis, who
will vote March 17 whether to give him a fourth term. Polls show
the premier neck-and-neck with opposition leader Isaac Herzog,
who has blasted him on the campaign trail for fumbling Israel’s
critical alliance with the U.S.

Campaign Tactic

Israel’s Central Elections Commission, concerned that
Netanyahu could use his speech as a blatant campaign tactic,
said it would be broadcast domestically with a 5-minute delay to
remove statements deemed overtly partisan. Pollsters say it is
unclear whether the speech is helping or hurting Netanyahu’s
Likud party.

In the course of 48 hours in Washington, the Israeli leader
will also recruit support at the American Israel Public Affairs
Committee’s annual policy conference.

The sour relationship between Netanyahu and Obama, which
predates the current disagreement, hasn’t interfered with
commercial and security cooperation between the two countries.

The U.S. remains Israel’s biggest trading partner and
closest defense ally, providing $3.1 billion in annual military
assistance. In business, trade between the nations has grown to
$38.1 billion in 2014 from $28.3 billion in 2009, Obama’s first
year in office, according to the U.S. Census Bureau.

‘Grave Threats’

Netanyahu’s blunt challenge to Obama comes at a delicate
time for both. Obama has lost Congress to Republicans that hope
to use the next two years to reverse his accomplishments and lay
the groundwork for a presidential win in 2016. Their invitation
to Netanyahu is part of that effort.

Boehner rejected criticism by Obama’s national security
adviser, Susan Rice, who said Netanyahu’s public confrontation
with the president over Iran was damaging the U.S.-Israel
relationship. Rice is also due to speak at the AIPAC meeting.

“What is destructive in my view is making a bad deal that
paves the way for a nuclear Iran,” Boehner said at a Feb. 26
news conference. “That’s destructive, and that’s why it’s so
important for the American people to hear what Prime Minister
Netanyahu has to say about the grave threats that we are
facing.”

Policy Divide

While Netanyahu’s speech is mired in politics, it also
represents the most fundamental policy difference between the
two countries in decades. There has long been tension over
Israel’s treatment of Palestinians as well as over American arms
sales and relations with Arab countries. But the gap over Iran
is of a different order of magnitude.

Netanyahu has argued for years that no development would
threaten Israel as much as an Iranian nuclear weapon. Such a
weapon, he says, would immunize Iran against military action and
could be passed to Iranian-backed anti-Israel forces like
Hezbollah in Lebanon and Hamas in Gaza. The deal being offered
the Iranians will force a delay, he says, not an end to their
nuclear program.

Obama counters that he fully agrees about the danger of an
Iran with nuclear weapons, and that the accord he’s seeking to
reach with Iran will prevent that and work toward luring the
Islamic Republic back into the family of nations by slowly
reducing sanctions.

In Iran, top officials including the conservative Supreme
Leader Ayatollah Ali Khamenei have publicly supported a deal.

Easy Choice

Netanyahu’s clash with Obama has caused a backlash in
Washington that undermines the Israeli leader’s objective of
influencing Congress, said Ilan Goldenberg, a senior fellow at
the Center for New American Security in the U.S. capital.

“The people he really needs to target are the Democrats,
specifically the fence-sitters on the Democratic side, and they
now feel as though they have been put in a position where they
have to decide between the Israeli prime minister and the
president of the United States,” said Goldenberg, a former
Senate staff member and State Department official. “As much as
they are strong supporters of Israel, it’s not a very difficult
choice for them — they’re going to choose the president.”

Republicans hope to benefit from the tension. Jeb Bush, a
likely 2016 presidential candidate, told the Israeli newspaper
Israel Hayom in an interview published Friday that Netanyahu
should be heard because he is right and the White House wrong on
the Iran deal.

Father’s Grave

Netanyahu’s decision to address Congress may spring not
only from a deep concern about Iran but also a belief that
public speaking is one of his strengths. He first came to
American attention as a diplomat in the 1980s and appeared
frequently on television making Israel’s case, especially during
the first Gulf War.

Among Netanyahu’s preparations for this trip was visiting
the grave of his father Benzion, a historian who infused his son
with concerns about the dangers facing the Jewish people.

Posting on his campaign’s Facebook page, Netanyahu said:
“I will continue to follow his path. I will go to the U.S. to
make Israel’s position heard on the developing nuclear agreement
with Iran, an agreement that will provide Iran with nuclear
arms.”

To contact the reporters on this story:
Jonathan Ferziger in Tel Aviv at
jferziger@bloomberg.net;
Terry Atlas in Washington at
tatlas@bloomberg.net

To contact the editors responsible for this story:
Alaa Shahine at
asalha@bloomberg.net
Bruce Stanley, Randall Hackley